#RPGaDay2025 - 14 - Mystery

It's RPGaDay season again. Here's a link to the blog post with the current year's prompts.

Today's prompt is Mystery. 

My favourite roleplaying scenarios involve mysteries, no matter what the genre is. If you gave me the choice between trying to solve a case, or understand the horrors lurking behind an event, I'm all in. This is because it plays to my own nature in real life. Professionally, I am often involved in root cause investigations and analysis, and the mystery format really engages the same part of my brain. 

I start to try to pull data together and find the links and connections, and love it. The example above is from the Eternal Lies campaign which became so big that I couldn't maintain this kind of mapping. I know my natural tendencies enough that I'll either play a character that would naturally think this way or I'll act as the custodian of the clues for the party as a whole.

I do get frustrated with poorly written mysteries where the authors haven't pulled the interconnections together clearly. If you're writing - or running - a scenario in this space, you really should understand how everything fits together.

The diagram above shows me doing this for The Hunt for Sabre IV, an adventure from Mysteries on Arcturus Station for Traveller. I had to do this or clues get lost in the pages of text, and I think you need them to be to hand if you're GMing a scenario.

You don't need to use specialist software for this; there's plenty of ways to approach this. I used the free version of Miro for the first diagram, and Scapple (£19 as I write this) for the second. The lowest diagram is a Microsoft PowerPoint organisation chart turned into a clue map for the Delta Green scenario The New Age.

Of course, you can do this manually. The page above is my handwritten notes on my reMarkable that show the adventure structure, links to clues, handouts and NPCs as a top level reference for one of the Shadows of Atlantis campaign scenarios for Achtung! Cthulhu.

Structure is really important in mystery scenarios. The Alexandrian has a great example of how to do this with the 3-clue rule, which I recommend reading even if you haven't liked at it before. Mapping a scenario lets you see the weaknesses in the design. In the Shadows of Atlantis scenario above, I ended up adding an additional clue to connect parts, however not everything could be addressed with this. In some cases I had to use 'the boffins back at HQ have studied the material and concluded this'.

City of Mist has some great advice on scenario design for mysteries (then has so many scenarios that you don't really need to do it!).

Cases have multiple locations which are interlinked on an iceberg map. This doesn't go as far as I have in the handwritten example, but once it's linked to the very clear design for scenarios, it makes it simple to read and use at the table.

There's an example page from the introductory scenario Shark Tank above. Yellow boxes call out clues, links to other locations are underlined and NPCs/dangers have bold text. If you are running the campaign that the game has, there are other clues highlighted in red that will come into play for other scenarios in the campaign arcs.

It's important to remember that clues don't have to explain, the merely need to be trail of breadcrumbs deeper into what is happening. It took us a lot of sessions in Eternal Lies to work out what was actually going on, and I think that some of it we only truly understood at the end. That was fantastic; it felt like we were groping around the edges with clues we were trying to connect.

Anyway, back to mystery. I love the use of mystery scenarios, and they need structure. I think that'll do for this entry.

14 August 2025