How to Create a Murder Mystery

Platinum Wizard of Adventure Arvindh asks:

Can you teach me how to create a murder mystery?

Sure. A quick caveat before we begin though. A TTRPG murder mystery experience is different from a book or film.

With static and scripted mediums, the audience is passive. Writers rely heavily on information silos to keep the audience guessing. They strategically choose which questions characters do NOT_ _ask, direct where the camera lens doesn’t point, and control time and movement.

We GMs don’t have a passive audience. We have active players, and they control their own characters. So the experience will be different. Avoid expectations that an RPG murder mystery will play out like a book or a show.

Murder Mystery Generic Process

  • Choose the Murder Victim: Who is it?
  • Determine Crime Location and Time: Where and when did it happen?
  • Determine the Murderer and Method: Who did it and how?
  • Create a Murderer’s Timeline: Start with their waking moments and detail their day, leading up to the murder, then their actions taken after the crime to the present moment. Our timeline is the foundation for our entire adventure.
  • Develop the Cast of Characters: Create a spreadsheet or table of legitimate NPC suspects. For each one, detail their motives, backstories, and alibis. Some might have strong alibis, others might have weak ones, and a few may have no one to corroborate their story. Flesh out their relationships with the victim and each other.

This process forms our mystery’s Core Logic. The facts and other details hang off it so things make sense. Logic Bombs are the bane of mysteries.

For example, perhaps the cloaked murderer was spotted, a chase ensued, but it failed. So, we want to detail the witness, time, and place of this event and decide what the murderer intends to do about the danger of a potential witness. We should also decide what the witness thought they saw.

The Three-Clue Rule

A common problem for GMs is what happens when players miss a clue.

Instead of creating a single, linear path of discovery, use the Three-Clue Rule. For every crucial piece of information the players need to move forward, provide at least three different clues or ways to get at one clue.

Here are some examples of evidence you could place:

  • A Witness: Maybe they can only offer a partial clue or identification.
  • Physical Evidence: Clothing with bloodstains, a discarded weapon, a personal item left behind by the murderer.
  • A Document: Diary entry, half-burned letter, or a ledger could contain a key information.

The players might miss the bloody boot, but they might find the witness or the document, and the game keeps going.

The Adventure Location

I recommend a location-based murder mystery, especially if this is your first time GMing one. Isolate all the suspects, victim, and PCs in a self-contained location like a mansion near the sea or an arctic research lab.

Why? NPCs are mobile, so we can’t control information through them unless they’re stationary, like a prisoner. Players will just round everyone up and interrogate them until mystery solved — yawn.

Instead, we add the plot points to specific rooms in the mansion, the hospital besieged by zombies, or the broken train gaining speed as the mountains approach. NPCs, which you can move as desired without hassle during play then point to those locations.

This keeps the game going and ensures the players have to travel to different areas for the solution, creating gameplay ahead.

Poke Holes in Your Plan

Once you have the core logic and clues, it’s time to find the gaps. Look at your adventure holistically and try to spot Logic Bombs:

  • Sub-locations: Do any rooms or hidden areas need maps and details?
  • Player Character Abilities: Study the character sheets. Are there skills and abilities that could change the game?
    • Spells (e.g., speak with dead).
    • Gear (e.g., a fully stocked CSI lab).
    • Abilities (e.g., detect lie skill or telepathy) that could end-run your plans?
  • Conflicts: Add a conflict (an interesting encounter of some kind) to every clue room and a few non-clue locations too. Challenge the players and make the characters earn the clues.

I suggest feeding your plot or adventure notes into an AI and ask it to poke holes in your plot, too.

Finishing Touches

Remember, our adventure is a living document even when it’s a murder mystery. Players will do unexpected things. But with our core logic figured out and made robust, along with multiple paths to the solution, you’ll be ready.

Cheers,
Johnn
roleplayingtips.com
https://discord.gg/6MxTRAqQ76
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