Sketch out the structure of your mystery adventure to keep things twisting for your party.
A good D&D game always benefits from rising tension, heightened stakes, and a grand finale. Knowing how a mystery story typically works and having some idea of where the party can go, who they can talk to, and when things are gonna start getting intense is essential. Without these story beats as a starting point, it’s easy to streamline to the solution, or have things drag out far too long.
Keep in mind that this isn't the only way to run a mystery. Nor is it confined to a crime like murder. Nor does it have to stay rigid. But what are the story beats that allow for any mystery idea to be dropped into? We first go to the Strategy Stateroom to find out.
The Setup
Introduce your suspects and hint at your antagonist.
The Crime
One step of antagonists plot
Clue one points to suspect one
Clue two points to suspect one
Clue three points to suspect 2, but allows for suspect one
Clue four points to suspect 3, but allows for suspect one
Introduce a ticking clock
The Investigation
Suspect one
Location
Encounter
Information that exonerates them and points to suspect two
Suspect two
Location
Encounter
Information that exonerates them and points to suspect three
Antagonist Interference
Suspect three
Location
Encounter
Information that implicates them and points to the antagonists trap
The Trap
The antagonist is one step ahead and lays a trap to take the party out.
The showdown
The party has just enough time to stop the antagonists’ plot
The Resolution
Wrap things up, all is explained. Unless there's a cliffhanger...
Then we go to Grandma B's Schoolhouse to figure out how players can get info out of NPC's without resorting to war crimes. Maybe start with some negotiation and interrogation techniques instead, you monsters!