Tips on Running a Murder Mystery RPG Session

I recently ran a session with a murder mystery plot and I found it incredibly difficult to put together compared to one of my more standard style D&D adventures. I read up on the subject some, worked out my plotline, and ran the session all in one day. It was pretty successful, according to my players, so I thought I’d share some tips I have if you want to do something similar in the future.

The best thing to do is start with “who done it” before anything else. Figure out the legitimate facts and the “answer” and work your way backwards. Along the way, develop your cast of characters who are red herrings or other potential suspects. One downside of working this way is that you may discover a character who is a more likely candidate as murderer, but if so, just tweak them in and make adjustments. But starting with the killer means you know your end point, your goal for the players to reach.

For structure, look at existing procedurals for guidance. You don’t have to reinvent the wheel here. The great thing about being a game master over being a fiction writer is, nobody has any expectations of originality in a game. In fiction, you have to get past the gatekeepers to sell anything and reach the audience, and they want to see things done differently than the way they have before, but if anything, players don’t often want to see things totally new- they want the familiar and fun. For the structure of my dwarven mining family and the murdered patriarch, I borrowed liberally from Knives Out.

Establish a “real” timeline with the facts, then build individual suspect timelines so you can answer the questions the PCs will ask in character. Gaps or conflicts in timelines can be an important clue to discerning players. Really flesh out your supporting cast. Give everyone a beef with the victim so there’s a plausible reason to suspect them all. Your players are going to interrogate them, so you really want to get inside their heads. Try to make them distinct, but again, don’t be afraid to lean into tropes and stereotypes. I have maybe 4 distinct character voices I can do, but you can give them verbal tics or personalities to make them stand out as distinct.

Structure the nature of the relationships such that you can encourage the players to question them in an order that fits your narrative. Giving the right information at the wrong time can completely undermine your structure in a murder mystery. In fiction, the characters figure out the solution at the right time and place for the narrative structure, but you have to work a lot harder when the characters are controlled by real people trying to actually solve the mystery. The only solution I found to this problem is to provide compelling information about everybody and only give clues to eliminate suspects late in the game so that they can begin to narrow things down only after a good build up.

For my mystery, I had four siblings that all stood to gain from their father’s death, and the players naturally took the hint of the birth order to question them, which meant that the actual murderer, the secret fiancee of the youngest son, really only came into the picture late enough that it felt like they were really doing the work to uncover the secrets.

Don’t be afraid for the players to get things wrong. Getting it wrong could end up being just as interesting as getting it right. Getting it wrong could make them new allies or enemies for life. Let the players think they figure it out right if they went entirely off base. Even consider changing your solution to make them feel successful if that matters to you more.

It’s not important here that you tell a good murder mystery on paper. It’s important that you lead an entertaining experience of figuring out a mystery. Let the players enjoy the paranoia of suspecting your entire supporting cast. Have fun listening to them discuss theories and analyze things. That’s where the real fun is, for me — listening to them debate and struggle and theorize. If you can do that, even if the landing isn’t perfect, players will still look back on the session fondly.

For instance, I don’t think that I did the best job of revealing the murderer. Ultimately, I did a good job with the cast and setting up clues, but the murderer was introduced too late and perhaps too obviously. Some lucky insight roles really saw through her – but keeping her introduction until relatively late, and not making her a prime suspect meant that the mystery unfolded at the pace I wanted, just at a minor cost of a little bit of narrative satisfaction that bothered me more than it bothered the players.

Really landing that “surprise” moment of who did it with smart, engaged players is nigh-on impossible, I think, but maybe it can be done. If you have any tips on how to manage that part, I’d love to hear them!

2 thoughts on “Tips on Running a Murder Mystery RPG Session”

  1. Lots of good ideas here!

    I haven’t GMed a mystery (or anything) in a while, but some things maybe worth noting:

    1. I’m not totally convinced that old problem Gumshoe sets out to solve actually exists—that is, I think most good GMs bypass Skill checks and just *give* players clues when they’re necessary to complete the adventure and the players look in the right place/way—I think the design assumptions of the Gumshoe system are interesting.

    Two two design assumptions I mean are that most of the player fun in an investigative game comes from the process of interrogating, debating, interpreting, and otherwise puzzling through the clues, and turning investigative skill use into a resource management game instead of a gambling (die-roll based) one can have interesting repercussions. You give players each skill-specific Investigation points based on their areas of knowledge, and when they auto-find a clue in a given locale, they have the option of spending one or more Investigation points to get more information linked to that clue (or other clues they otherwise miss). Players have to balance clue-FOMO against the instinct to reserve some points for later on when they might be more useful (or more desperately needed). There’s a supplement titled Lorefinder that was put out, which maps out how you’d apply Gumshoe mechanics to a D&D/Pathfinder game. I’m not sure I’d ever want to do it as completely as that book describes (with Investigative skills impacting combat and so on) but the general idea of Investigation being a separate subsystem/resource management minigame is at least interesting.

    Oh, and of course, when you’re assuming players will at least get all the basic clues, then it’s really more about building a network of false leads and evidence or alibis that eliminates them. (The optional something-extra clues can also occasionally be initially baffling or even halfway red herrings, but in aggregate they should help in narrow things somewhat in the long run.)

    As for how to make the surprise reveal work, it might be easier to do away with it: say, by a third of the way in, the players ought to be *pretty* sure which NPC committed the murder, but won’t be able to do much until they figure out *why*. Coming up with a big-reveal motive might be easier that surprising the players with which NPC did it: the youngest dwarf didn’t kill his father for the inheritance—he never wanted it—but instead because following his dad’s apparent religious conversion (or unexpected shift of political allegiance), he’d become steadily convinced that his father had been replaced by a doppelganger and wanted to save his family.

    Another way to make the reveal a surprise via motive would be to make the reveal ultimately be the doorway into a new, bigger, higher-rank mystery. I’m thinking of the Conspyramid concept from Night’s Black Agents. (If you search with that as a term, you’ll find plenty of diagrams and some worksheets for mapping Conspyramids, and even some work by people like Justin Alexander trying to apply the concept of the Consyramid to D&D-type games.)

    The idea here is a bit like what I described above about needing to find motive: whodunnit becomes either whydunnit or rather to a mystery of who’s a level up and pulling the strings. When you solve the question of whydunnit or who’s pulling the strings, then bingo: you move up to a new tier with its own mysteries of who and what and why. Night’s Black Agents is an espionage game, so it’s assumed players will work their way up the pyramid to the top, but in a fantasy RPG campaign, the reveal of someone higher up pulling the strings might not go that direction: players might say, “Damn, the Calzanian Duke pushed her into killing him… what a jerk!” rather than looking deeper and learning that the Duke did it at the behest of the Imperial Priestess Abras, for reasons connected to an ancient enmity between her church and the Subothians who live in the Kingdom beyond the dwarfholds, etc.

    Either way, this would soften the blow of a reveal whodunnit reveal that falls flat: the real reveal is why (who at-whose-behest), rather than who.

    Oh, and I totally agree about not being too married to one solution: players sometimes come up with much crazier and more interesting motives for crimes, and feel very pleased with themselves for puzzling out your brilliant mystery: no sense in disabusing them of this notion. (That said, it can also be fun if, after a suitable amount of time passes, it turns out they were utterly wrong and are responsible for some Poor NPC who’s been rotting in the dungeons because of their mistake, or who comes looking for revenge, or who worms their way into the group’s community and starts plotting against them.)

    Incidentally, for me the thing that would give me a headache would be figuring out ways to structure the mystery so that I wouldn’t have to do that cheaty trick of, “Here’s a list of spells that don’t work for this adventure,” while also making it so resourceful players can’t just magically shortcut their way to the solution. There’s ways of doing it, of course, but it’d just require so much more careful consideration. (Sort of like how coming up with a sensible, non-plot-holey mystery that can’t be solved super-quick gets harder after the invention of DNA-identification and cell phone records checks and so on, except worse, because it’s magic, after all.)

    Though timing can also help, I guess? The Wizard loses her traveling spellbook in a fire, the cleric ends up in the theological doghouse for a misdeed (and denied divine spells)… hey, guess what, there’s this murder that needs solving!

    Man, that was long-winded.

    1. Jeremiah Tolbert

      A lot of food for thought here!

      I did cheat my way out of some of the spells, but in hopefully a fun way. I made it so that using “truth” or mindreading spells was against Dwarven law (violates free will) so the interrogation room was an anti-magic field. Laws against that kind of magic make sense to me.

      Second, I did something that I thought was pretty clever which was the poison used to kill my murder victim was a special poison favored by assassins that prevents the dead from speaking to the living or being resurrected. It stands to reason that assassination in a setting like Faerun would have to develop something like that to make death permanent or assassination is more of an inconvenience than anything else.

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