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Running Investigations and Mysteries

by Mike on 11 March 2024

This article is one in a series where we look at types of adventures and examine

how we prepare them.
how we run them.
what pitfalls we might run into.
how we avoid these pitfalls.

These articles include:

Your own adventure types and how you run them may differ from mine. That's totally fine. There are many right ways to enjoy this game.

Robin Laws's book Adventure Crucible – Building Stronger Scenarios for any RPG inspired my thoughts on this topic.

Understanding Investigations and Mysteries

In investigation and mysteries, one or more previous events have occurred which have led to the current situation. The characters spend their time in the adventure learning what happened and potentially changing the course of future events based on what they find. During investigations, the characters talk to people, explore locations, uncover clues, and face those foes who seek to thwart them.

Mysteries are difficult to run because, unlike narrative fiction, we don't know where the characters are going to go, what they're going to investigate, or what clues they might pick up. They could identify the key villain in the first scene or pursue tangents away from the clues you expect them to follow. Both of these situations need to be accounted for in your prep and play.

Preparing Investigations and Mysteries

These steps can help you prepare to run an investigation or mystery:

Develop the starting situation. What happened? Who did what? What is the timeline of previous events?
Develop your strong start. How and when do the characters get involved in the situation? What hooks them into the mystery?
Develop a list of NPCs the characters can talk to. Who are they? What was their involvement in the situation? What do they want? What are their goals? Avoid introducing the main villain too early if you're trying to keep them a secret.
Develop locations the characters can investigate. Where can they go? How can they uncover the clues they eventually need? What happened at these locations?
Develop a list of secrets and clues. Keep them abstract from their place of discovery so you can drop in these clues when it makes sense based on the investigation undertaken by the characters. In investigations and mysteries, you may need more than ten.
Write down monsters and treasure for the more traditional adventure elements.

Running an Investigation or Mystery

The following list provides a structure around running investigations and mysteries:

Use your strong start and sink in the hook so the characters, and their players, want to dig in and figure out what's going on.
Introduce NPCs helpful to the characters who can give them a push in the right direction.
As the characters investigate, drop in clues that lead the characters to other locations, meeting other NPCs, and discovering more clues and so on.
Throughout the adventure, expose clues until the players can piece together the whole scenario.
Add henchmen or other hostiles to add some combat as desired.
When the time is right, drop in your villain and have a big confrontation.

Common Pitfalls for Investigations and Mysteries

Investigation and mysteries may sometimes include the following pitfalls. During prep and play, keep these pitfalls in mind so you can avoid them and run a fun evolving game.

There's only one way to find the right clues and the characters don't follow it.
The characters discover the villain or source of the mystery too early.
The characters never discover the villain or figure out the mystery.
The GM leads the players on too much – making it clear the players didn't figure it out but had the results spoon-fed to them.
The pacing gets tiresome. Players who want to crack some skulls end up bored.
The mystery is too complex. Players can't figure out all the important details.

Avoiding Pitfalls

Consider the following ways to avoid the pitfalls listed above.

Keep the clues needed to uncover the mystery abstract from their location of discovery. Drop in clues along the path the characters take during the investigation.
Don't introduce the villain too early. Keep them a blank spot in the story until it's time for their revelation.
Provide the right amount of information for the players to be able to piece together the puzzle themselves. Don't spell it out for them.
Clarify that the characters are the ones discovering information and piecing it together – not you the GM.
Have multiple ways to uncover the truth. Don't let discovery of the mystery hinge on a single element the characters might miss.
Include combat and skirmishes to keep combat-focused players interested.
Keep in mind that players only grasp about half of what you reveal. Keep mysteries simple enough that players can actually piece them together.

Build Situations, Not Mystery Novels

A key to running a good investigation and mystery is not to assume you know how the players will discover the truth. Build and set up the situation during prep and let the characters follow their own path to their ultimate discovery.

More Sly Flourish Stuff

The Lazy DM's Companion is currently on sale for 50% off the PDF and 20% off the PDF and softcover version! If you don't have this book, now is a fantastic time to pick it up! The Lazy DM's Companion includes tools, tables, and tips for running awesome fantasy D20 games. Grab it today!

Last Week's Lazy RPG Newsletter

I had a cold last week and didn't record an episode of the Lazy RPG Talk Show (also available as a podcast). Instead, I wrote a text-version of the talk show in the Lazy RPG Newsletter for 3 March 2024 with news, tips, and Patreon questions and answers.

I did post a YouTube video on Using Paper Character Sheets.

RPG Tips

Each week I think about what I learned in my last RPG session and write them up as RPG tips. Here are this week's tips:

Name villains and sentient opponents. Make each one unique.
Have players identify monsters with interesting physical characteristics.
Add an interesting usable environmental object or effect into significant combat encounters.
Tie clues, treasure, and MacGuffins to the backgrounds, knowledge, and history of the characters.
Reveal the world through the eyes of the characters.
Ask each character what they think about from their past and their current larger goals during short or long rests.
Show the characters the results of their actions in the world.