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This standard reference document provides the GUMSHOE rules made available via the terms of the Open Gaming and Creative Commons-By Attribution licenses. It is a reference for game designers, and is not tuned to teach the game, or provide a playable game experience. If you’re looking for a playable game, seek out such Pelgrane Press titles as The Esoterrorists, Trail of Cthulhu, Ashen Stars, Night’s Black Agents, Mutant City Blues, or Fear Itself. Or watch for games the users of this license will build with it.
Notes appearing in italics within square brackets provide guidance for designers basing their own games on these rules. Avoid unsought hilarity (and violation of the OGL) by remembering to cut them from your finished manuscript.
This document provides text you can cut and paste into your games. It naturally assumes that you have acquired a fundamental understanding of GUMSHOE by reading and extensively playing at least one GUMSHOE game. When creating core rule books, you will want to interleave this text with examples of your own devising, which show new readers how the rules work, and, at the same time, convey the tone, spirit and entertainment value of your setting.
This open license document does not grant rights to use the settings of Pelgrane’s GUMSHOE games. You might however use it as the basis for generic scenarios GMs can adapt to their horror, space opera, or spy thriller GUMSHOE worlds of choice.
Investigative abilities allow you to find the information your character needs to move forward in a mystery-solving narrative, plus occasional additional benefits.
General abilities help you survive while you’re gathering information and solving problems. You create characters by spending build points on your character’s abilities. Each ability has a numerical rating. Every rating point costs 1 build point to purchase.
The GUMSHOE rules define your character by what he or she can accomplish in an investigative scenario. The component elements of each ability don’t matter in rules terms. The rules don’t care if your Forensic Accounting ability is one part native mental acuity to two parts training or vice versa, although you can mention them when describing your character to others. All that matters is how you solve cases, and overcome other obstacles arising from them.
Ratings and Pools
The number you assign to each ability is called a rating. Although you may improve them gradually over time, ratings remain static over the course of the typical game session.
For each ability your character has a pool of points, which fluctuates over the course of each session. You begin each case, or scenario, with pool points equal to your rating. You might then immediately spend some of them during a prelude phase to the investigation itself. You will definitely spend points as you conduct the investigation. At times your pool may increase, sometimes refreshing to equal its rating again.
The distinction between ratings and pools is a crucial one; keep it in mind as you read and interpret the GUMSHOE rules.
Step One: Concept
[Describe the sorts of mystery-solving characters the players will play in your setting, and any preliminary creative decisions each player will make about her character.]
[In some games you may wish to guide players to choose genre-appropriate concepts by supplying a list of stereotypes as a starting point in character creation.]
Sample Stereotype: Good Girl
The good girl is an ordinary young woman. If not chaste, she's more modest and circumspect about her sexuality than the other young women in the cast of characters. Smart and cautious, she becomes the ultimate prize of the shadowy forces stalking the group—often proving herself more determined to survive than those around her.
[From Fear Itself]
[In some games you may choose to give additional mechanical heft to the stereotypes by turning them into Packages.]
Each package sets out minimum requirements in both Investigative and General abilities. Before spending any points elsewhere, make sure you have those covered.
Sample Package: Communications Officer (Hailer)
You establish, receive and route communications with other ships, planetary installations, and space stations. More than a glorified space receptionist, you serve as a combination of public relations frontperson and psychological warrior. You facilitate the decision-making process of the crew and convey its intentions to the outside world. In crisis situations, you keep vital information flowing to the stratco, so that the right decisions get made at lightning speed. During space combat, you launch hack attacks on the enemy’s computer system, while defending your own from penetration.
General: Communications Intercept 6, Sense Trouble 4
[From Ashen Stars]
[A variant of the Package sub-system, the Occupation, appears in Trail of Cthulhu. Rather than providing minimums to qualify for a package, an Occupation provides key abilities at half-price, and often a Special mechanical benefit as well. Future Pelgrane GUMSHOE designs will likely stick to the faster, simpler ability minimum approach found in Packages.]
You get two rating points in Occupational abilities for every one build point you spend. For example, 12 rating points of Occupational abilities cost you 6 build points. Left over half-points are lost, so assign an even number points to Occupational abilities.
Sample Occupation: Private Investigator
There are things that cops can’t do, and things that cops won’t do, and you’ll take money to do either. Sometimes you get dragged into something the cops want you out of, but you gotta stay in it to keep the cops honest. What keeps you honest? Now, that’s the real mystery, ain’t it?
Occupational Abilities: Accounting, Disguise, Driving, Law, Locksmith, Photography, Assess Honesty, Reassurance, Scuffling, Shadowing.
Special: Private eyes with point pools in Disguise or Shadowing may spend points after rolling the die for a test. For every 2 points you spend after rolling the die, you increase the die result by 1. This only applies if you are undistracted and not directly observed. It never applies during a contest. You must describe the thing that almost went wrong, and how you caught it barely in time or succeeded through sheer luck.