GUMSHOE is a system for designing investigative roleplaying games and adventures, emulating stories where investigators uncover a series of clues, and interpret them to solve a mystery. In GUMSHOE, the players always get the clues they need to move the narrative forward.
In a GUMSHOE game, you create player characters (PCs) by choosing your character concept – the sort of mystery-solving character you want to play – and then spending build points to buy ratings in Investigative Abilities and General Abilities.
Investigative Abilities allow you to find the core clues your character needs to move forward in a mystery-solving narrative, and give occasional additional benefits.
General Abilities help you survive while you’re gathering information and solving problems.
Every GUMSHOE scenario begins with a crime, conspiracy, or other act of disorder committed by a group of antagonists. The PCs must figure out who did it and why, and put a stop to their activities. Game Masters (GMs) design a GUMSHOE adventure by creating the following:
- An investigation trigger. This is the event that attracts the attention of investigators.
- A sinister conspiracy. This sets out who the antagonists are, what they’ve done so far, what they’re trying to do, and how the investigation trigger fits into the overall scheme.
- A trail of clues. Working backwards from the sinister conspiracy and their plans, the GM designs a trail of clues leading from the investigation trigger to an understanding of the sinister plot and its players, sufficient for the players to get to work destroying it.
In a GUMSHOE game, the PCs progress from scene to scene, interviewing people and using their Investigative Abilities to find core clues, which advance the story and help the players solve the mystery. If a scene contains a core clue and a player character uses an Investigative Ability relating to that clue, the character will find it.
Investigative Ability ratings also function as pools, from which players can spend 1 to 3 points to get additional clues, providing more information or other benefits about the situation. Investigative Ability pool points are refreshed between scenarios.
General Abilities are used when the outcome of an ability use is in doubt, like at dramatically important points in the story, or for tasks of exceptional difficulty. For these tests, GUMSHOE uses a six-sided die, which is rolled against a Difficulty – usually 4, although it can be modified from 2 to 8 depending on how hard the GM thinks the task is. If the die roll is equal to or higher than the Difficulty, the PC has succeeded in her action.
A player can spend as much of their General Ability pool on a die roll as they want – each point spent adds 1 to the roll. General Abilities pools are refreshed between scenarios, and sometimes during play.