So I released this deck for Blades in the Dark. You can see the process for using the cards under the heist outline. Here’s a fast example heist; it is not only a demonstration, but a ready-to-go heist a GM could insert into a game as-is.
Spoiling the Punchline
The crew is contacted by a nervous small-time offender, who tells them if they know what’s good for them they’ll accept an invitation to a tavern near the city offices for the Crow’s Foot District. If they go, they find two big bodyguards protecting a back corner, where a plump grandmotherly woman wants to talk to them.
She is Commissioner Naria Haig, one of the sharpest politicians in Duskwall. She wants their help. Holtz Clermont is the City Clerk for the Crow’s Foot District. At city expense, he has retrofitted one of the towers that houses equipment for the Lightning Walls that protect the city from the starving swarms of ghosts outside, so its defenses can also be applied to certain sensitive treasures seized in the course of enforcing the law.
She has come to find out that in a raid that uncovered some illegal treasures, never mind where, Clermont noted the acquisition of the Combination Harpsichord. This artifact has tuning pegs attached to crystals and runes, so playing certain chords and progressions can affect the Ghost Field and its perception.
Clermont retrofitted the tower because it is rumored to be the last resting place of the Censer Mace of Udoch, where the noble family entrusted to its safekeeping hid it in a “shadow room” that only exists in the Ghost Field now. They hid it so well no one could find the room, much less find a way in to it.
Now Clermont is in the market for a whisper who can use the Combination Harpsichord to find the ghost room that is hiding the censer mace. If he gets that object he can retire in style and with significant influence in the Church of the Ecstasy of the Flesh (who will also be emboldened, if they get the artifact.) The weapon’s head opens, and if a certain incense is burned in it, the weapon can (according to legend) slay ghosts and demons with a hit.
Commissioner Haig wants to hire them. She controls significant wealth, but maybe more to the point, she can affect their Wanted rating. She wants that censer mace, she wants the crew to steal it for her before Clermont can get it. She doesn’t care if they have a Whisper who gets hired and betrays him, or if they find the hired Whisper’s identity and subvert her or him, or if they know an eerie musician who can use the Combination Harpsichord to best effect; their methods are up to them, and she’ll do her best to shield them from the worst of the consequences should things get ugly. She doesn’t even care if they loot other valuables from the lockup (including evidence of crimes committed by the crew, or other crews.)
Defenses are fierce. The tower has a massive plasm generator. Some of that energy is routed to some strategic door handles and floor plates, to shock intruders who don’t know not to touch them. Also, several defensive points have lightning walls installed, miniature versions of the great walls that protect the city. Finally, the exact location of the shadow room is not known, and it may have defenses within that Commissioner Haig can’t know about. And, of course, well armed city guards.
Commissioner Haig concludes by telling them Clermont will waste no time now–he knows he doesn’t have forever to find the mace before he has competition. They might have hours, days, or up to a week, but he’s moving fast and they should too. Good luck!
Now the players start thinking about ways around those defenses, and the GM can start rounding out the heist with further twists and turns! But that’s enough to kick things off and let the glorious improvisation ramp up.
The idea here is that you could need a heist in short order, and generate one with the cards. You draw two important people, figuring one will hire you to hit the other one. Then you draw a treasure card; the heist has something to do with that. Finally, draw three special obstacles to add to the sort of obstacles you’d already expect.
Synthesize it all together, and you’ve got some inspiration for the heist location, and some ideas for how it all fits together. You can either do it fast, on the spot, or some time ahead and give your back-brain time to simmer over it and refine the ideas.