See Page XX: Designing Your Own GUMSHOE One-2-One Scenarios

A column about roleplaying

by Robin D. Laws

Whether designing for your home game, the GUMSHOE Community Content program, or an independent product using the Open License, the process of designing a scenario for GUMSHOE One-2-One breaks down the same way.

With a few adjustments, detailed here, the process matches that for designing a mystery for standard or QuickShock GUMSHOE.

I built GUMSHOE One-2-One on the assumption that the pressures and focus of running a game for a single player calls for a solid foundation of preparation. When you’re engaged with a player throughout the session, you lack the thinking time to heavily improvise your way through an investigative scenario that holds together in the moment and will make full sense in retrospect. In multiplayer, the group often misses key points in the chaos of discussion and speculation and never looks back. In a solo game the player is much more likely to spot plot holes you inadvertently leave in an on-the-fly session.

Standard GUMSHOE presents two main scenario structures:

* the maze of clues, which presents a flow between established scenes the players can navigate in several directions and to varying outcomes

* the ocean of clues, which lays out a broad situation, relying on player choices to create a narrative by seeking information, with the GM responding to each choice along the way

My scenarios tend to follow the maze model; Ken gravitates to the ocean.

For published One-2-One scenarios, and your own games when getting started, I recommend the tighter maze structure. These allow you to anticipate the Challenges you’ll need to create, described in greater detail below.

If designing a One-2-One scenario based on an existing GUMSHOE game, refer to the GM section of that book, where you’ll find its steps for scenario creation.

Let’s say you want to write a scenario more like the full-on Lovecraftian ones found in Trail of Cthulhu, as opposed to the mythos-noir mashup of Cthulhu Confidential.

Flipping to page 192 of the core book, you see that scenarios consist of:

  • a hook, the initial problem or question drawing the investigators into the mystery
  • the horrible truth, the much worse, Mythos-inflected problem lurking behind the hook
  • the victory condition, a scene or set of circumstances in which the character resolves the central mystery — but perhaps also realizes, in a jolt of cosmic unease, that true and final triumph over gnawing emptiness of the universe is impossible
  • antagonist reactions, scenes that can happen at any time, as the opposing cultists, creatures or other opposition forces of the scenario strike back at the investigator

You then build scenes into a maze of clues, as you would for multiplayer GUMSHOE, making four main adjustments (one of them optional.)

Before doing that, create the character who stars in your scenario.

This allows you to perform the first adjustment, making sure that the plot allows the hero access to Sources whenever she needs information outside her set of investigative abilities. Sources are the Game Master Characters the investigator consults when confronted with areas of knowledge outside her own expertise. So if your final sequence has the investigator plunging down into a Yithian complex buried deep under mysterious Davenport Iowa, write that bit so that she never needs an ability she doesn’t have. Once she lacks the freedom to visit one of her reliable band of experts, she can only rely on her own information-gathering skills.

The second difference between multiplayer and One-2-One scenario construction is that you create structured Challenges instead of the straightforward general ability tests found in Trail.

In a Trail scenario a Difficulty 4 Hypnosis test simply lists what happens when a player succeeds:

A character performing a Difficulty 4 Hypnosis test permits another to remember his


For One-2-One, you instead build a Challenge and create its associated Edge and Problem cards, as detailed on p. 44 of Cthulhu Confidential.

Advance 6+: Miles recalls his dream. Also, you are able to implant a suggestion of emotional resilience, protecting him against any further dangers that may lie in wait for him. Gain the Edge card “Power of Suggestion.”

Hold 4-5: Miles recalls his dream.

Setback 3 or less: Miles falls into feverish nightmare, shrieking and groaning for mercy. Gain the Problem card, “Price of Hubris.”

Extra Problem: The process of hypnotizing Miles dredges up your own dread worries of Deep One ancestry. Gain Problem card “Ancestral Glimmerings.”



Proposing an outcome that makes story sense, spend this card to allow Miles to extricate himself from any situation.



-1 to tests of Mental abilities.

Discard when you fail such a test.



That fear you suppressed over the family portrait you found in Innsmouth comes back.

Mythos Shock.

Like other Mythos Shock cards, Ancestral Glimmerings might come into play in the Emotional Coda, which brings us to the third adjustment between multiplayer and One-2-One scenario designs. Find places in a standard scenario where a character might die, and instead design that point of suspense into a Problem card that only activates at the end, after the mystery has been solved.

In multiplayer, one investigator might be shot to death in the middle of a session. The player creates a new character while the others continue on, waiting for a moment where the replacement might credibly arrive.

In One-2-One, the character takes a Problem card:



Discard by Taking Time to get your bullet hole sewn up by a competent doctor or equivalent.

If still in hand at end of scenario, you die.

And finally, preferably during the victory condition scene but maybe earlier, try to write in a scene that emphasizes the character’s aloneness and lack of backup. A particular event at the end of “The Fathomless Sleep” can only happen to a solo character, and plays out as a memorable moment again and again, for multiple GMs and players. I don’t want to spoil it but if you check out the scene you’ll see what I mean. Scenarios don’t absolutely need this element, but they sure pay off when you can fit them in.

To recap, then, scenario design for One-2-One requires XX adjustments from multiplayer:

  1. check access to Sources
  2. create Challenges
  3. move character demise to coda
  4. (optional) find a signature moment that underlines aloneness

GUMSHOE One-2-One retunes, rebuilds and re-envisions the acclaimed GUMSHOE investigative rules set for one player, and one GM. Together, the two of you create a story that evokes the classic solo protagonist mystery format of classic detective fiction. Can’t find a group who can play when you can? Want an intense head-to-head gaming experience? Play face to face with GUMSHOE One-2-One—or take advantage of its superb fit with virtual tabletops and play online. Purchase Cthulhu Confidential and other GUMSHOE One-2-One products in print and PDF at the Pelgrane Shop.

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