Gamemaster’s Guidepost: Building a Mystery

Adding a mystery angle to your campaign is not something that’s particularly hard – doing it well on the other hand can be tricky. GURPS Mysteries by L. J. Steele is a fantastic, must-have resource for GMs running a mystery campaign for any system, but especially useful for those running GURPS campaigns as it contains notes on just about every paranormal power that could be taken and how they might impact a campaign.

Regardless, here are a few tips:

Establish the Beginning, But Leave Ending Fuzzy
GMs for any genre can get caught up with the end result to the point that they have blinders on in any game, but it can be even worse for a detective mystery, cozy, or “who dun it?” Thus, the best thing any GM can do is firmly establish the framework of the mystery itself, the beginning contextual clues, and then the probable ending. Don’t be afraid to change it depending on what the PCs do. Nothing is more satisfying to a player than to make an out of game guess and be right.

“Endings are hard. Any chapped-ass monkey with a keyboard can poop out a beginning, but endings are impossible. You try to tie up every loose end, but you never can. The fans are always gonna bitch. There’s always gonna be holes. And since it’s the ending, it’s all supposed to add up to something. I’m telling you, they’re a raging pain in the ass.”

– Chuck, Supernatural #5.22 “Swan Song”

Don’t Be Afraid to Leave Loose Ends
Seriously. Don’t. Loose ends are ok when gaming (and when writing, really) because for the most part the end of one story arc is just the beginning of another and having loose ends helps create a feeling of continuity between one story arc and the next – assuming you use said loose ends at a later date.

Additionally, there is something to be said for never explaining a mystery. Simply present the main plot and something ancillary and then never explain the latter. Life never provides all the answers all the time and neither should a game.

Don’t Be Afraid to Hit Them Where It Hurts
You want to involve a player or player characters in a mystery plot? Hit them right in the feels. Hard. Want to have them chase a serial killer? Have them murder a friend, contact, ally, (or if you’re really mean) a dependent. (Note: doing the latter you should absolutely offer to either replace the dependent in some way or let them buy it off or swap disadvantages for equal points – Guilt Complex, Manic Depressive, Over the Edge, Obsession, etc.) Bring in their past somehow and let them know it. Maybe their parents didn’t die in a car accident or maybe their best friend didn’t run away after all. Regardless of what you do hit them where it hurts. Doing this will usually have the player invest heavily in what you are running and provide for satisfactory gaming.

Do note that you must be careful when doing this and you should definitely warn your players something might happen.

Brilliant Characters and Gaming
We all like to play characters who have traits different from our own. Gaming lets us do that. But there can be issues when running a mystery when the character is highly intelligent, perceptive, etc. and the player is not. Therefore the GM must improvise a little bit. Perhaps he gives the player advice on something his character would notice about the scene or allows him extra rolls to put two and two together. Whatever you do, be aware of the player’s capabilities as well as the character’s. It can be incredibly frustrating when the GM creates a challenge for the character, while ignoring the player.

Every Detail Is Important Until It Isn’t
One of my players pointed out an interesting thing while I was running my game – the GM never describes an element or gives information that’s not important. And that’s mostly true. Gaming takes time and most of us don’t have but some many hours to waste pursing the hobby – this creates a kind of “inverted” importance situation. If everything the GM describes is important than the players must pay attention to everything the GM describes. This in turn means the players can take contextual clues from the descriptions and more easily solve the problem. Veteran gamers do this without thinking most of the time. So how to fix it? Describe random things that have no importance, but won’t significantly impact the storyline and distract the players.

Picking Over the Bones
In the end, adding mysteries to your campaign is going to take time and work to make them something the players want to pursue. Knowing your players is also something you just have to do as well because things can get so convoluted when running mystery games that the details have to be kept straight in both the player and character minds.

So what things do you do when running mystery games? What advice can you offer your fellow GMs? Any particular technique you use or used in the past that worked particularly well?

Posted in Gamemaster's Guidepost and tagged , .


  1. I've only run 2 mysteries. My first was very railroady and pretty terrible. The second was many years later when I had become a better GM. In the latter I knew who did it (murder) and how, and placed my clues, some of which were red herrings. The players (and characters) latched onto more red herrings than "real" clues and rather than having them lead nowhere I had them implicate the wrong person.

    So when the big heroes brought the "murderer" back to town, the townsfolk stoned him to death in a frenzy. The characters felt bad, but knew that justice had been done.

    Fast forward 3 or 4 sessions later, the characters found a letter from the real killer to his lover, gloating about how he'd gotten away with murder (with details, like a simple Frenzy potion in the well had driven the townsfolk to kill the wrong man, ensuring there would be no further questions).

    What I learned from the experience is that solving a mystery incorrectly can be just as fun (because they think they solved it) and fictionally satisfying (because it lead to all kinds of great story telling) as solving it correctly.

  2. Railroads aren't bad – as long as the players know ahead of time that's part of the game plan. I really should have put that up there too – there is no "correct" way to solve a mystery as long as everyone is having fun.

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