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How To Run (Murder) Mystery Adventures in D&D

Last year I researched and wrote Candlekeep Murders: The Deadwinter Prophecy, a murder mystery adventure for 5th edition Dungeon & Dragons that I’m immensely proud of… hey, if Ed Greenwood gives you the thumbs up, you can afford to pat yourself on the back a little, right?

My research not only included taking in the advice of many D&D bloggers and Youtubers, but it also involved rewatching some favourite movies like The Name of the Rose, Clue and Knives Out, and taking in a fair few classic episodes of Agatha Christie’s Poirot, such as Death on the Nile and Murder on the Orient Express, amongst others.

William of Baskerville examines a clue in Name of the Rose (image: picture-alliance/dpa).

It was a fun process, during which I made many interesting observations. Equally as fun was putting everything I learned to use in the writing of Candlekeep Murders. I think it’s high time that I shared my insights.

Before I offer up my design tips, I think it behoves me to define what a mystery adventure is, in the context of D&D and other RPGs. And my conclusion is this:

A mystery adventure is one in which the players must gather information in order to answer a question. 

Why did the girl disappear? Who stole the pink diamond? Where is the microchip hidden? These are the types of questions that kick off a mystery adventure. And, obviously, if you’re looking to run a murder mystery then the question is: Who killed X?

Looking back at my 9 different types of RPG adventures, another simple way to define mystery adventures would be ‘Investigation quests’.

I’ve penned the following tips primarily from the point of view of a Dungeon Master intending to write their own mystery story (and possibly even publish it), but I think they should also prove useful for GMs running third-party investigation scenarios as well. Finally, some tips are specific to murder mysteries, and may not be applicable to every adventure (I didn’t feel it was worth splitting the two topics however, especially given that the most iconic type of mystery adventure is the murder mystery).

***SPOILER ALERT FOR MY PLAYERS***. A rather specific spoiler alert, but if you are one of my players who hasn’t already played Candlekeep Murders, DO NOT read this post, as it contains major spoilers.

Time to play detective in Forgotten Realm’s most famous library….

Tips For Running RPG Mystery Adventures

1. Don’t Write a Trivial Mystery

If a question like ‘why did the girl disappear?’ can be answered easily by searching a single room or speaking to one specific NPC, or it can be shorted by a single magic ability, your session is going to fall flat. (Similarly, if you’re writing a murder mystery, but you give the players a chance to intervene, and they prevent the assassination and arrest the would-be killer, you also have a problem). Players approach a mystery adventure, expecting to have to exercise their brains for several hours, and I think the biggest mistake for DMs would be to construct a trivial case for them to solve.

Some specific tips on how to prevent this from happening:

  • Ensure that the information that needs gathering, to answer the question behind the mystery, can’t be gained by finding a single clue, visiting a single location, or interviewing a single person.
  • Start by running mysteries for lower level characters, who are less likely to be able to shortcut the scenario with game-changing magic or class abilities.
  • Familiarise yourself with low level divination spells (and their limitations). More on this in the Prepare for Magic section
  • In the case of a murder mystery, tell the players that they not only have to identify the killer, but build up a convincing case against them so they can be brought to justice. Sure they found the smoking gun, but they need to find out the killer’s motives and/or disprove their alibi in order to construct a watertight case against them.
  • Add some complications to the story. See the section on Plotting.
  • Have a back up plan, just in case the mystery is resolved ahead of time. If the players find the murderer more easily than you were expecting, have that segue into a new stage of the adventure. Perhaps now they have to find out who the killer was working for. Maybe the assassin confesses that other agents are at work this very night, in an attempt to purge ALL of the Masked Lords… the party have to act fast!
  • Read some mystery adventures that have survived playtesting and play those first, before writing your own.

2. Don’t Write a Mystery That Depends on ONE Vital Clue

Probably the most commonly-occurring piece of advice you’ll find online about running D&D mystery adventures is don’t let the solution of the problem hinge on finding a single clue – especially one that requires a skills check to find. If everything depends on the players finding a coded, singed note in the fireplace, what happens if they don’t search the fireplace? Or they search the fireplace but fail their Perception / Investigation check? Or they find the note, but they don’t realise it’s a code, or don’t manage to decode it. I’m not going to link to the Alexandrian’s Three Clue rule for the umpteenth time… so here’s his video on the matter instead.

Cheat mode: A related trick to keeping the mystery on track is to have two or three ‘Floating Clues’ up your sleeve, i.e. objects or pieces of information that the party can find no matter where they look. One foolproof device is the NPC who comes to the players, when they get stuck, with a fresh reveal… you can still have the PCs work for it however, by having the NPC demand something valuable in return.

3. Avoid a Linear Clue Path Altogether

Related to the above, if you plant a single clue that leads to another specific clue that leads to another, which eventually leads to the answer, then you’re not only risking your story arriving at a dead end (when players miss, or misinterpret, any of the vital clues in the chain), but you’re also creating a rather linear gaming experience, with players chasing the plot down the road, rather than leading the investigation themselves by deciding where to go and who to speak to. Plant clues that open up various branches of enquiry, and give the players the satisfaction of taking up the reins of the story.

Advanced Tip: If you’re planning a complicated mystery, you might want to make a clue tree, in which you map out all the potential info the PCs can gather and where they can find it (‘where’ might be from a person in many cases). You might want to write what the clue is, where it can be found, and what the clue reveals (or might reveal); and, as discussed, you’ll want to give the players several different ways of arriving at the same conclusion(s).

The crime scene often provides the base of your clue tree…

Finally, on the topic of clues, there’s a school of thought that says don’t make player roll to find them. If they search the room, they find all the clues in the room. More clues, equals more fun, and offers a better chance of the adventure running smoothly. I am not fully enrolled in this school, so let me share how I handle searches. If the player states the specific part of a room where a clue is hidden (“I search the fireplace”), unless the clue is especially well hidden, you can assume they take a thorough look and find the clue without having to make a check. But if they just say “I search the room” I would say, “ok you spend 15 minutes searching the room: make an Investigation check,” and reveal a number of clues in relation to the strength of their check (potentially including any in the fireplace). If they roll badly, you’ve tacitly built in the option for them to spend longer investigating, if they have the strong hunch that there’s more to be discovered. And if that’s too metagamey for your tastes, you can make their roll behind your screen. In this way, if they decide to continue searching it’s a tactical decision, not them reacting to a bad roll.

Generally speaking, if you have at least 4 people in the party, you can almost guarantee a pass on any DC 10 Perception or Investigation check, if everyone gets involved, and even DC 15 will be passed far more often than not – so you can let the players have the satisfaction of rolling for clues with the expectation they will find them. Note: the guidance cantrip, contrary to common wisdom, is not really useful for search checks however… read why here.

4. How To Plot Your Murder Mystery

So you’re staring at a blank OpenOffice document and wondering how to start planning your mystery adventure? Consider these points and you should be well on your way…

I. Who Was The Victim? And Why Did Someone Want Them Dead?

First you need to figure out who died and why. A powerful figure makes for a great victim, because as well as all the typical reasons anyone might get murdered (jealousy, revenge, unpaid debts), there’s also plenty of political motives you can bring into play. Was the spirited Duchess murdered because she cheated on her husband, or was she murdered because she refused to be bribed on the matter of land reforms?

In Candlekeep Murders it’s none other than the Keeper of Tomes (aka Chief Librarian!) himself who gets murdered, just before he can announce his successor, and just after an epic argument with his lover. Now we have a scenario whereby multiple people might desire, or benefit from, his death (see section on Providing Multiple Suspects).

II. Who Is The Killer & What Was Their Weapon of Choice?

Probably, when you considered the killer’s motives, your imagination gave birth to the killer too. Now consider their choice of murder weapon, because an iconic modus operandi will hook your players (or potential buyers, if you plan to publish) into the story. I’d advise choosing something either cool/rare, or else something thematic to the story. Investigating the murder of someone garrotted by the string of a lute is a more memorable case than if the victim died from a knife in the back.

Scorpion, ice bath or meatgrinder all beat a knife in the back…

As for a thematic death, you could choose something to do with the story’s location or atmosphere (more on Evoking Atmosphere later). For example, that same lute string garrote would also become a thematic killing method if the murder took place in a music school full of preening rival bards.

For Candlekeep Murders, a story that takes place in Faerun’s greatest library, I used a book whose pages had been dusted with midnight tears (probably D&D’s coolest poison!) as the offending weapon (yes, I did steal adapt that from the Name of the Rose).

III. Create a Murder Timeline

One thing that was instrumental in helping me write my own mystery adventure was creating a timeline of the murder. This helped ensue that the murder that I wrote was actually possible to pull off, and when DMing the adventure I had something to refer to when it came to players questioning witnesses etc. You will also want to include what any other suspects were doing at the time, and in each case you might want to include what they say they were doing when questioned (when this is different to what actually happened). Writing a murder timeline, should also help you build clues that the murderer left in the build up, execution and fleeing of their crime.

A crime timeline can provide a sturdy reference tool for DMs (and inspire new clues).

Overall, I think a murder timeline is just a great tool to prevent you from tripping yourself up… if you know the murderer left through the snow at midnight, then you know anyone arriving after midnight will have seen their tracks. If you are attempting to make this kind of thing up on the fly, you might stumble at the table. Players will have their detective hats on and be paying attention to details they normally wouldn’t zone in on during a routine D&D session.

IV. Consider The Crime Scene & Initial Clues

Assuming that the players get to investigate the crime scene (if you wish them to inspect the body, you might want to invent a reason why it hasn’t been moved… in a medieval-based fantasy world corpses would likely be carted off, not left around for private dicks to examine), this will likely form the base of your clue tree. Ideally, you want to plant clues that offer several diverse leads, each heading in different directions, giving players autonomy in how to tackle the investigation (not just heading from A to B to C, as we discussed previously in Avoid a Linear Clue Path).

V. Develop Key Locations, Suspects & Witnesses

After investigating the crime scene, where will your players go, and who will they want to speak to? It’s time to join the dots of your story, as the player-detectives set about gathering various pieces of information (clues), at various locations, from various people. By the time they’re done, hopefully they’ve gathered a body of evidence that should point towards the killer.

VI. Create Some Complications

All good stories feature complications, and your adventure is in danger of being a trifle dull if the players are allowed to mooch around finding clues in their own time, completely unmolested by external forces. Consider sticking in a ticking clock (I wrote a detailed post on the topic you might want to check), or have the killer take action against the heroes, once they realise they are hot on their trail. Otherwise, any complication you might throw in a normal adventure, should work here too… just avoid interrupting the story with some unrelated trouble that might break the atmosphere of the case.

VII. Plan The Adventure’s Resolution

Great, the players work out who the killer is! But now what? Do they have to present their evidence in front of a ‘jury’? Is the killer in the room (see ‘closed circle murders’ and the section on Providing Multiple Suspects below), ready to refute them? Does the murderer go quietly… or do they attempt to flee or fight? Do they have any allies ready to protect them?

This is D&D, not an episode of Colombo, so personally I’d try to finish your story with a boss fight or climactic action scene, esp. if your adventure was action-lite up until now.

5. Make Gathering Information Interesting…

As discussed, mystery adventures are essentially investigations and the success of your session (i.e. how fun it is) is going to be based around how sexy you can make the process of gathering information. In other words, a couple of Investigation checks and a perfunctory chat with an obliging barkeep ain’t going to cut it. Try this instead:

  • Use Diverse Clues. Clues might be objects (often accidentally discarded), traces of objects (blood, footprints), written testimonies (notes, letters, business papers) or oral testimonies (witnesses). In the case of the latter, that could mean tracking down sly, corrupt or cantankerous NPCs trying to solicit reliable info from them (note: be sure to roll their Insight checks behind your DM’s screen!).
  • Use Witnesses. In general, witnesses are one of the best clue-giving devices, as social interaction is easy to make fun in RPGs by creating some memorable NPCs – so be sure to include some. They needn’t have witnessed the murder necessarily, but they might have seen a whispered conversation in the corridor that aroused their suspicion… (leading to the question: “and what were you doing in the corridor at midnight, Mr. Witness?”). Great tension (or laughs) can also be leveraged by uncooperative witnesses, possibly with their own secrets to hide. And remember, in D&D, animals (and even plants… see Prepare for Magic) can be witnesses too… be sure to give them their own personalities. One of my favourite NPCs in Candlekeep Murders is actually Queenie the Cat, who considers herself the true boss of Candlekeep, while the Keeper of Tomes is merely her Cuddler in Chief.
  • Include Exploration. Build some exploration into the investigation, by hiding clues in cool locations. Speaking to witnesses might also involve travelling to memorable places.
  • Use Diverse Skills Checks. Hide information behind diverse skills, especially those that rarely see play in your typical D&D session. Now’s the perfect time to wheel out the lesser-spotted Medicine check, as well as all the other knowledge-based skills that many DMs fail to bring to the game (in my experience). The player who took Religion will be delighted if it’s required to ascertain the identity of a statuette… and if no one passes the check, they will have to waste time asking around town (a good rule of thumb in D&D is to use failure to create a cost, rather than a dead end).
  • Call for Some Tool Checks! That goes double for Tool proficiencies, which are (finally) given a chance to shine in a well-constructed mystery adventure. It’s easy to think of scenarios where proficiency in the poisoner’s kit, herbalism kit, calligrapher’s tools, cobbler’s tools or forgery kit would offer advantage on a skill check, or allow them to make a check that others have no chance of passing.
  • Use Multiple Success Points on Checks. I am not sure if I invented this device, or stole it (and if I did ‘invent’ it, no doubt others had independently ‘invented’ it before me), but in Candlekeep Murders I made frequent use of skill checks that offered accumulated successes on increasingly higher DCs, using a single roll. This ‘degrees of success’ style check proved fun for both me and the players, rather than the usual binary pass or fail, with the bonus that it is also more efficient than calling for multiple rolls. To illustrate, here’s an example of a ‘Multiple Success Point’ Medicine check in Candlekeep Murders which players can make to examine the Keeper of Tome’s corpse. Every checkpoint passed reveals the information of all lower checkpoints as well:
    • A successful DC 5 Intelligence (Medicine) check reveals that the Keeper’s heart is missing, but no other organs.
    • A DC 8 checkpoint, on the same roll, reveals that the Keeper’s ribcage was smashed by what appears to be an axe, or similar, using several precise blows, all very close to one another.
    • A DC 12 checkpoint reveals something strange: while the Keeper of the Tome’s vestments are covered in blood and cruor, the mess is surprisingly localised around the wound. (One would expect spurting jets of blood to have covered not only more of his robes, but also more of the room).
    • A DC 15 checkpoint reveals that the victim’s nose is fractured and bruised.
    • A DC 20 checkpoint reveals that the victim’s eyes are reddened and their tear glands are peculiarly swollen: faint tear tracks indicate that the victim cried copiously before death.
  • Allow Room for Deduction. To allow your players to truly feel like detectives, you shouldn’t be feeding them the answers, even when you present them with a clue. A bit like with secret doors, you shouldn’t be calling for an Investigation check and then, when they roll high, state: “hey presto, you pull the chandelier and a hidden door opens in the west wall.” You should be saying, “you notice traces of mud leading from the desk to the west wall.” In the example above, a DC 12 checkpoint reveals that the blood is localised around the wound… the deduction, which I leave out, is that the Keeper was already dead when his heart was hacked out, meaning there was no blood pressure to send jets of blood spurting over his chamber. Ergo, the axe, or similar, was NOT the murder weapon!
  • Include Some Action. Vary things up, by including some physical danger. Hiding some info behind a combat, or hazard, can be a good way to ensure that every type of player remains engaged in the adventure. To prevent a session of just dialogue and exploration, consider creating a scenario where speaking to the bandit queen means taking out her henchmen in the taproom first.
  • Leverage Puzzles. For mysteries, of the non-murder variety, puzzles can be a fun way to hide information, as unlocking them can be satisfying and on brand for this cerebral type of play. Puzzles can be hard to fit into standard adventures convincingly, but they can often make sense when trying to solve the ancient mystery of the missing artefact, for example, in which a wizard left clues for the worthy to rediscover it when the time is right. For murder mysteries, your typical assassin isn’t going to set up a method for the players to catch them, however, perhaps the victim hid his will in a cryptex. Or perhaps the killer is one of those insane genii that toys with detectives, and DOES leave a deliberate trail, in the form of a puzzle, hoping to find a worthy mental adversary. Remember to account for the players not being able to solve the puzzle however!

Puzzles can add to the cerebral fun of a mystery RPG adventure

6. Provide Multiple (But Limited) Suspects

The reason closed circle mysteries work so well in films and novels are twofold. The first is the tension of knowing the murderer walks amongst the innocent (even better if everyone is trapped / stranded in the same location)! The second is that it gives the audience enough suspects to keep them guessing, without so many that they have no chance of solving the murder from their armchairs. When someone is murdered in a busy marketplace, we have no way of guessing who that assassin might be… there’s no shortlist to draw from … and it’s the same in D&D. The murderer is an abstract quantity. In a closed circle, the murderer is right there… they just have to figure out who it is (and why they did it).

Imagine a scenario in which the first clue hints at a murderer who was short of stature, the second of someone who had the keys to monastery dorms, and the third clue is a note begging someone called G. for more time to pay their debt. In this instance, we’re just constructing a case where Gedri the dwarf janitor is prime suspect from the off and later clues simply confirm the suspicion. That’s fine, but it’s not maybe the Sherlock Holmes fantasy you were hoping to create for your players.

A roster of suspicious characters in Knives Out (image: Media Rights Capital).

By providing multiple suspects with a reason to kill the victim, you are setting the scene for a more satisfactorily complex investigation, during which players will have to examine, and maybe cross examine, several people and compare their testimonies to established facts and events. You can make it even more fun by giving each ‘innocent’ suspect their own secret to hide, even if they are not the killer. In Candlekeep Murders, Sylvira Savikas is not the killer, but neither is she a cooperative witness – after all, she wants to hide the fact that the Beast of Candlekeep is her own demon-spawned son. These secrets add depth and intrigue to your story, and keep your players guessing longer.

7. DO Use (Certain Types of ) Red Herrings

Probably the second most parroted piece of advice on running mysteries in D&D is don’t offer your players red herrings, with the common wisdom saying they will jump to plenty of incorrect conclusions on their own accord, and bark up plenty of wrong trees. I agree with this advice up to a point: for example, adding a ‘fake’ clue that leads to a dud location is generally a waste of everyone’s time (eg. a snuff box, with the logo of a warehouse, which was dropped by a random passerby – not the killer – is just undramatic and frustrating).

However, as discussed, you are going to want at least one other plausible murder suspect if you want to build a more complex Agatha Christie style story, and one or two of the clues the players find during their investigation should point to their possible involvement in the murder. Part of their job is to keep on gathering information until the weight of evidence points to the true killer, but for that to be a challenge, there needs to be some evidence that doesn’t immediately point to the true assassin.

8. Prepare for Magic:

Maybe one of the trickiest aspects of writing or running a D&D mystery adventure is taking into consideration the abilities and spells that players can use to gather information that no real world detective has access to. It’s one reason why you might want to consider making your murder mystery a 1st level adventure, because it limits a lot of the problems you will have, while also solving another problem: the fragility of 1st level characters shouldn’t be much of an issue in a mostly cerebral adventure, so even more reason to kick off their careers with a mystery story.

On the other hand, where one D&D designer might see magic as a threat to their adventure, another savvier one might spot opportunity. Some of the small print of spells can lead us to add some awesome details to our story. In my adventure Candlekeep Murders, the First Reader wants to protect the murderer from being discovered decides to hack out the Keeper of Tomes’ heart so that he can’t easily be raised from the dead, meaning that the case starts with a mutilated body. They also cast speak with dead on the victim, to ensure that the spell won’t work again for another ten days (yes, they could have hacked off his jaw as well, but psychologically speaking it’s harder to hack off the face of your old boss, than open up their chest).

Now you’re just cheating!

Let’s take a look at some problem spells, with a focus on the divination school of magic, and how you might deal with them (with difficulty at times… more ideas welcome in the comments section please!).

Remember, however, ideally you don’t want to have to resort to shutting down the players’ powers. If a player takes a divination spell instead of the typical evocations ones, it’s precisely because they want to shine in these types of investigative scenarios, and they’ve sacrificed some of their combat effectiveness to do so. Our goal is not to stop them shining, but just stop them ruining the adventure. If they are able to shortcut it slightly, that’s great… if they can obtain the answer to the mystery’s question simply by expending a single spell slot, then you’ve designed a poor D&D mystery.

Before I start, I’ll remind DMs of one really important factor, which often gets overlooked in my experience, and that is casting a spell is not something you can just do when surrounded by polite society. To begin casting a spell is the arcane equivalent of drawing a sword and waving it around, and players shouldn’t be expected to be able to cast a spell in the middle of a council meeting for example, without being rushed by the guards – who might suspect the caster is about to unleash a fireball, for all they know.

Additionally, many settings have laws against using magic, such as Waterdeep where the Code Legal states that ‘Using magic to influence a citizen / official without consent’ is a crime.

Overall, the D&D mystery designer’s best friend might be social or legal restrictions on the casting of spells, with the advantage that players will accept that more readily than the convenient appearance of multiple anti-magic zones, or a surprising amount of mindblank-ed commoners running around.

1st Level Spells

Comprehend Languages. Expect that players will be able to understand any uncoded written clue (although see Illusory Script if you want to make an exception!).

Command. You might want to make NPC saving throws behind your screen, in case the cleric starts shouting ‘Confess’ at every potential suspect (or upcasts it to target the whole room!). In general, designing murderers who are proficient in Wisdom saving throws is always a good idea. Meanwhile, you could argue that being magically compelled to confess would make you confess even if you’re innocent… the arcane equivalent of a forced confession under duress… thereby rendering such a command almost useless to a just jury.

Detect Evil & Good. Shouldn’t be a problem unless your murderer is really a vampire in disguise. Ditto an aberration, celestial, elemental, fey or fiend in disguise. Nystul’s Magic Aura could be used to counter DE&G.

Detect Magic. More likely to be a solution, than a problem, you can hopefully count on players picking up some useful, but not vital, info with this spell. Does reveal the school of magic as well. If you do need to counter it, however, Nystul’s Magic Aura might come to the rescue again.

Detect Poison & Disease. Potentially useful to the players, but delivers nothing you wouldn’t expect a few successful skills checks to do.

Find Familiar. One of my all time least favourite spells, this ridiculously useful utility spell needs to be taken into account when designing any D&D adventure, not just mystery ones. Having a telepathic critter be able to sneak into any room and retrieve info, set off traps and spy on NPCs is just obscenely overpowered for a spell that doesn’t even require a spell slot to cast. This is one that I would personally ban, but I’ve also made a house rule, as yet unplaytested, which might help – esp. if you add in some stray cats to any locations you want the players (and not their pet gerbil) to explore.

Illusory Script. Could be a good device to hide a clue behind, but for advanced players only I’d suggest.

Speak with Animals. A D&D mystery designer has to bear in mind that any animal appearing in the adventure is a potential witness. DMs can have a lot of fun with animals though, who might like the understanding and depth of vocabulary to explain many humanoid behaviours.

2nd Level Spells

Detect Thoughts. This is a nasty one! The caster can read the surface thoughts of any targets before a saving throw even, and on a failed saving throw they can probe deeper and gain insight into ‘something that looms large in its mind’, making this a potential mystery killer. However, this is a highly intrusive spell that is an open act of aggression on the target, who might easily strike at them (causing them to lose concentration), while anyone with counterspell would attempt to counter it. It feels like something that you could use on a prisoner, but not on a noble for example, who might call for their arrest or have their house guards attack. You could also consider giving your murderer access to the spell mindblank, but that in itself is suspicious behaviour and also requires for your murderer to be an archmage (or friends with one), so it feels like a bit of a spammy solution. A magical item that guarded against detect thoughts would make more sense, esp. if the players can guess that the headband the noble wears protects them, and make that a plot point – “we must find a way to steal his headband so we can get to the truth of the matter”. As with certain other spells, your best bet might be roll your saves behind the screen… not an ideal solution, but better than derailing the adventure IMHO.

Locate Animal or Plant. If you’re planning on having the players traipse through a jungle to find a rare breed of orchid, then know this spell.

Locate Object. If your mystery revolves around finding a lost object, you might want to refresh yourself on the text of this spell. Luckily, it comes with an out built in… a thin sheet of lead blocks the spell. I used this to create a nice plot point in Candlekeep Murders… Bookwyrm hides the Keeper of Tome’s heart in the chalice of a lead statue.

Suggestion. See Command. I feel like targets of these spells how pass their saving throw, should either have advantage on subsequent saving throws, or immunity for 24 hours.

Zone of Truth. For me, players need to embarrass NPCs to agree to speaking under the influence of this spell: “If you’re innocent, then why wouldn’t you tell the council what happened that night under the divine will of my god?” Otherwise they would just refuse to speak for 10 minutes, or be incredibly evasive.

3rd Level Spells

Clairvoyance. Enables the party to gather information from a location they know, but unless you want it to, this won’t break your adventure.

Speak with Dead. The oft-cited murder mystery buster is anything but, and one of the least problematic spells on this list. Even if the murder victim saw the murderer (which is unlikely in many cases, including any poison cases), the spell has three outs built into its description. The first is the corpse has to have a mouth (or you might rule tongue), the second is that the spell doesn’t work if the corpse was the target of this spell in the last 10 days, and the third is that it can only answer 5 questions and in a brief and often cryptic and repetitive way. “Who murdered you Gerald?” “My enemy.” “Which enemy?” “My greatest enemy.” etc. etc.

Speak with Plants. A bit like speak with animals, be careful how many flower pots you put in the murder victim’s bedroom.

Ok I think I’ll call it there, but obviously if you’re planning to write an adventure for players of 7th level or over, you’ll have to take a look at other divination and mind control spells etc.

Resurrection Magic

A word on resurrection magic. If the murder victim is someone important, medium-rich or with important, medium-rich allies and lives in a big city, you might want to consider why they are not brought back to life using raise dead (5th level spell, that can resurrect anyone dead less than 10 days for 500 gp). Certainly if your player characters are 9th level you may have a problem here (although the attempted murder might still need solving). I actually touch on this issue on my post about Temple Rituals, which offers NPC priests a way of performing resurrection magic, but without the ease or surety of a 9th level divine caster.

Other Problematic Powers:

Wild Shape. As insanely useful as find familiar, but at least it’s a player character doing the work, not an NPC rodent. Consider that your druid will want to turn into a bloodhound at some point (you might rule they have never seen one… but a wolf also has a good nose). Comes online as 2nd level, so another reason to make your adventure a 1st level one. Or you could give your murderer access to the pass without trace spell (if the players are smart they might deduce from the lack of tracks that the murderer is a spellcaster, thus narrowing their search). Meanwhile a crime scene might have all manner of conflicting scents lingering on it.

Ear for Deceit. This is rather overpowered for a 3rd level ability IMHO, giving Rogue Inquisitives (sourcebook: XGtE) an almost unerring Insight, esp. if they also spent their expertise slots on the skill. If you took my advice and created several plausible suspects, and gave them each secrets to hide, then Ear for Deceit shouldn’t present you with too many problems. If everyone is acting shady, then pinpointing the murderer will still require a full investigation.

Portent. Usually used to ensure enemies fail a crucial saving throw (it should probably be restricted to rolls made by the divination wizard… I will add that to my House Rules!), this could be adventure-breaking in combination with Detect Thoughts etc.

No doubt there are many more, but these are the low-powered abilities I can think of that are a bit different to the spells I tackled.

9. Why Are The PCs Hired To Investigate?

Perhaps not essential, but I think your story will be more satisfying if you build in a credible reason why the players are put in charge of solving the mystery. The average bunch of misfits that make up an adventuring party probably wouldn’t be anyone’s first choice of detectives, so I think it’s worth engineering a reason why it’s them that get the call. In the case of a murder mystery, perhaps their recruiter doesn’t trust the local authorities. Or maybe the case calls for an outsider’s impartiality. Or perhaps the quest giver wants the detectives to fail, as the murderer is a relative of theirs. Hell, they might even be the murderer themselves.

10. Evoke An Atmosphere

Again, edging on the advanced level of adventure design, I think the best mysteries evoke a certain atmosphere, usually through their environment. Death on the Nile has a certain colonial, sensual decadence to it, whereas The Name of the Rose has a desolate bleakness about it, as murders unfold in a bleak mountaintop monastery in winter.

Inspired by The Name of the Rose, for Candlekeep Murders, I adapted the wintry vibe but juxtaposed it with the cosiness of Deadwinter (i.e. Christmas) celebrations. By inserting lots of little details, like a bone-freezing wait outside the closed gates of Candlekeep, restorative flagons of hot mulled wine, accompanied by the scents of cinnamon and cardamon, in the Hearth, and a richly-decorated Deadwinter tree in the Readers Dining Hall, I like to think I gave more life to my story and provided a more vivid and memorable gaming experience for my players.

11. Include A Twist

Players love being surprised, and while the convoluted (and frankly non-sensical) plots of certain Hollywood films are dangerous and impractical to emulate, it’s good to have at least one joker up your sleeve. Maybe the killer wasn’t working alone (maybe the whole community were in on it, Wicker Man style!), maybe the person who hired the party was working to undermine them the whole time (with a view to framing them for the crime!), or maybe the solving of the mystery leads to an even bigger one… the killer was magically compelled to commit the crime, but even they don’t know who their puppetmaster is. Or the stolen artefact is located, but it has different powers to those expected and now threatens the community (a villain had conned the party into retrieving this ticking timebomb!).

12. Have a Plan for if the Party Stumble or Fail

It’s possible, even likely, that the players might reach a dead end in their investigations at some point, or get certain details muddled in their heads. To help prevent this, strongly encourage them to make notes from the beginning (impress on them that they are about to embark on a mystery adventure and notes are required, even if they wouldn’t usually bother!), and then encourage them to assess, or reassess, their evidence and clues gathered, from time to time.

Don’t be afraid to correct them on a false assumption, esp. if it’s born out of misunderstanding of the truth of the game world, rather than a bad deduction. But it’s still better to correct the latter than have the game fall flat. If you want to remain as impartial as possible, you could call for an Intelligence check to give away a clue, or even eat of an Inspiration ‘point’ for having to correct a misinterpretation. One thing’s for sure, if the players start to head down the wrong metaphorical tunnel, don’t let them go far before making it obvious that they’ve taken a false turn.

If, even with a little nudging from your part, the heroes can’t make enough headway for the case to continue, it’s worth having a plan of what happens. Maybe their inability to solve the crime means that the murderer strikes again (which has the advantage that fresh clues etc. will come into play), or maybe the quest giver asks for their money back and tells the party to leave town, with their tails between their legs. Maybe an NPC solves the crime, and becomes a new rival of the party. Or perhaps some other external events overtake the plot, carrying the players into action of a different kind. The players might be disappointed they couldn’t solve the mystery, but at least the session and/or the campaign continues.

More Resources on Designing RPG Mysteries

Here are some of the videos I watched before writing my own murder mystery, all of which were helpful to some degree or another and worth a watch if you have time.

What Are The Best Mysteries You Have Played?

I want to develop this post with a list of the best ever RPG mystery adventures and already have a few in my reading folder, however I’d really appreciate any reader tips on great adventures out there, D&D or otherwise.

Also please share your own tips on how to run investigations, and any success (or instructive failure) stories you’ve had at the table. Comments section below…

More of My Favourite Posts on H&D…

7 Haunting Horror Stories for Halloween

Journeys Through the Radiant Citadel: Review & Ratings!

Tome, Sweet Tome! Reviews of All 17 Candlekeep Mysteries

Designing Unforgettable Combat Encounters for 5e D&D

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3 Comments

  1. Justin

    This is really detailed and thoughtful advice, thanks Duncan! One of the early encounters in a published campaign I’m going to run features a serial killer, but as written it has some of the pitfalls you mention (probably as a result of simply being one ‘mission’ in a long campaign, rather than a standalone adventure where it can breathe), not least a very linear through-line. I will definitely sprinkle in some of your suggestions to lift it up!

    One source you didn’t mention is the Gumshoe system – are you familiar with it? It’s definitely from the “making the game not about finding clues, but about interpreting them” school (and I suspect where most DND folks are getting that maxim from). There’s also an old Gumshow-Pathfinder mashup called Lorefinder, for integrating Gumshoe investigations into PF games – this has reminded me to go back and re-read that book because the principles and concepts should be easily enough adapted to 5e/pf2e games as well.

    • duncan

      Hi Justin

      Thanks for the kind words.

      I am not personally familiar with the Gumshoe system, but definitely saw it name-checked a few times in the course of my research. I leave a link here, because it looks interesting:

      https://en.wikipedia.org/wiki/Gumshoe_System

      Some of the adventures / sub-systems written for it sound really cool too. Did you play any?

      Cheers for the recommendations!

  2. Rick Coen

    Duncan, great post! Took me awhile to read through it – wanted to make sure I had time to really absorb what you were saying. Definitely bookmarked for later! The current campaign has level 7 players – and a “read anything” Warlock [Eyes of the Rune Keeper, IIRC], so the few mysteries they run into tend to be of the “you find the information easily… but what does it mean??” variety. I especially like your analysis of the expected impact and thwarting of common spells. Again, kudos!

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