The Purchased Brother: One-Shot Heist

on running a one-shot heist / a game accelerating rule (criticality) / the story of the Purchased Brother / aftermath

A few days ago I ran a test of a heist one-shot over discord and it was one of the best games I’ve run recently. Everything clicked and the players snuck through the adventure and out the other end in just a little over 3 hours.

I’ve tried to run (and failed at) one-shots many many times over the years, but this time it worked. I attribute that to the following:


  • Assume PC agreement to the heist as part of the setup. All of the PCs want to be there. None of them has to be “convinced” to participate. If necessary, retcon the details later in chat.
  • Present a clear quest and use exposition. No faffing about. Metagame as required.
  • Do a quick “off-stage” purchasing round, if the PCs require anything up front, and allow for a retcon later (use a quantum item that turns into something the PCs require if needed).
  • Cut from the quest-giver scene straight to the opening of the heist. Boom. action.


  • As the GM, move action along. Is the outcome clear in a scene? Ask the players if they’re ok with the outcome, then narrate and cut forward.
  • Only use rules as needed. When you forget a rule, just ask the player if certain odds of success sound ok to them, then roll. Keep going. Time’s short.
  • Don’t make players guess what’s in your mind – give out clues when they go in the right direction and build on their ideas.


  • Use simple rules that you’ve memorized. Any rule that I didn’t remember in the moment, I didn’t use (see above).
  • And I added one rule that I called “acceleration” but should maybe have called “criticality”:


A player may, at any time, choose to succeed when they [would] roll. They can do this before rolling [a d20] or after, turning a failure into a success.

Every time a player does this, 1 criticality is added. I used a d12 to increment criticalities.

The number of criticalities in play represents the chance of a critical failure when PCs roll dice (so, no criticality = no chance of crit failure, 7 criticalities = crit failure on a natural roll of 1–7 ).

The number of criticalities also represents the chance of a critical success when the GM rolls dice, especially attacks (again, no criticality = no chance of critical hit, 7 criticalities = crit on a natural roll of 14–20).

Criticalities reset to 0 after every critical hit rolled by the GM.

Criticality, March 2023

In play, the criticality meant that failures were instead an opportunity for PCs to push their luck – increasing the tensions, since the odds things blowing up in their face kept going up each time they failed and resorted to a criticality to keep moving forward.

It worked wonderfully and by the time they got discovered and faced the chief antagonist, the stacked up criticalities meant there was a serious risk of a single attack taking out a character.

In the event, they barely got out, but there was palpable tension as the final roll to escape in a flaming sky chariot came with a 35% risk of critical failure at the end … and the pilot PC ended up rolling a critical success (natural 20) instead. Emergent narrative indeed.

The Purchased Brother

I started by outlining the key characters of the story and the opening scenes, and sharing those with the players. This saved me from having to run through everything during play and set the scene fast.

The PCs were:

Ostea the Thief

Hazuzu the Necromancer

Ilya the Gungineer

Opening Locations

You begin here:

New Increase – the many-augered city on the Lapiz Bay.

Old Increase – the rings of dead buildings girding New Increase

Eternal Road – where the dead must go, like the millions who already went before.

Skyfront – the great standardstone ramps and pads where the sky chariots once dwelled.

Columbaria – downtown, where the chitin bulbs hang like so many bundles of grapes on the old buildings of steel and glass, creating living homes for the city’s teeming thousands.

New Palace – the old bureau of civil engineering, still unbroken these ten hundred centuries.

Old Palace – trapped within a bubble of self-digesting time. Look how entropy has had its way upon the evil ones within.

Opening Characters

These are the characters you know right now:

Wit – the newly elected warlord of New Increase

Jorxe – corpse, former head of the Iron House, in coffin

Elle – the daughter of Jorxe, the lady of the iron house, aggrieved … due to lead the funeral cortege.

Cue Opening Scene

After we’d said hello and had a bit of chit-chat, I cut straight to the opening scene. I roughly described the funeral cortege of Jorxe, former head of the Iron House, wending its way along the Eternal Road to the funerary arcology. I asked the players for some input, and it turned out the huge floats were being pulled by grickles (menial, soulless species created Long Ago to toil in the fields and increase the well-being of humans by the sweat of their brows).

From there I cut straight to Elle, explained to the players that she knew the PCs (either by reputation or previous acquaintance), and opened with the problem:

her brother, Khal, was imprisoned (for trying to assassinated the newly elected warlord, Wit, with a bomb) and to be sold to the wizard of the Silver Ship tomorrow. She wanted the PCs to save her brother from the Silver Ship.

I asked the players roughly what amount of cash their PCs would see as a generous reward (some of them were flail snails PCs) and then increased that a little.

After all, the point wasn’t to stiff the PCs, but to give them a solid motivation to perform the heist.

Then, Elle provided them with a paschal key, which could pass any door for a drop of her family’s blood, and gave them also a vial with three drops of her blood.

This item performs the role of a sonic screwdriver from Dr Who, to let the PCs keep moving in the heist, but limiting their ability to break the game beyond the one-shot.

Elle also provided them with a position in the Iron House’s gift cortege, so they could access the Silver Ship.

Off-screen Prep

Next I quickly ran over the structure of the Silver Ship and the wizard Idrargo who visited New Increase once every 20 years to purchase all its prisoners. I answered all their out-of-character questions and then quickly ran over the kind of equipment they could have ready — rope, grappling hook, night vision goggles, things like that.

Then we cut to the next scene.

Enter the Silver Ship

Here I sketched out the standardstone ramps, the elected warlord and his metal guards, the processions, the festive air as the Purchased and the Guests are welcomed on the silver ship.

Again, I shared the regions of the Silver Ship directly:

Silver Ship – Idrargo’s great celestial ship, the bidecennial visitor

Atrium – the entrance hall where the all-consuming all-fire burns to remind visitors of Idrargo’s power.

Lustgarden – the landscaped pleasure gardens which remind visitors of Idrargo’s benevolence.

Feedladder – the terraced food gardens and houses of the vulpen grickles.

Manners – the accreted palace of Idrargo, lonely home of San Ikbal.

Butterfly Cage – the polyhedonic quarters of Idrargo’s purchased humans. (where the brother, Khal, was probably headed)

Distillery – the temple of the soul mill, where the purchased are sacrificed to prolong Idrargo’s life.

Square House – Idrargo’s house at the top of the silver ship.

The Atrium and the Wizard

In the Atrium, we played out the citizens’ reception by the wizard, who greeted each guest personally. This gave me a chance to share the wizard’s character and personality directly with the PCs in a non-threatening situation (after all, they were there legally and by invitation). This turned the wizard from a terrifying, creepy immortal entity into … a person.

Honestly, I think this bit of roleplay helped make the rest of the heist much stronger.

From there, the guests (and the PCs) were invited to the Lustgarden, and there the shenanigans of the heist began.

I won’t go into the details of what happened. Suffice to say, the criticality rule helped the PCs get deep enough into the Silver Ship, fast enough, that when they were discovered, things suddenly became very very dangerous very very fast.

  • Feats of cunning in the labyrinth were performed.
  • The butterfly keeper provided a weird sidetrack into soul-stealing butterflies.
  • A shooting gallery was hacked to provide a distraction.
  • An artificial waterfall was navigated to enter the Silver Ship’s infrastructure.
  • A silver-robed servant of the wizard was trapped in the shower and their robe stolen.
  • Torture and personality transfer chambers were investigated.
  • Three more sets of robes were acquired.
  • The brother was found and “persuaded” to robe up.
  • The wizard’s palace was entered, searching for the fabled sky chariot they all knew existed _somewhere_.
  • The wizard’s poet-companion was found and left alone.
  • A secondary body of the wizard was awakened, angered, and fled from (nearly killing Ostea the Thief).
  • The wizard’s necromantic chamber was activated and Atlas paid in blood to lift the PCs to the wizard’s house.
  • A tome was copied for the PCs by a helpful (duped) vulpen grickle, the private garden was entered long enough to spot the sky chariot on the roof …
  • And as the portal swirled for the wizard Idrargo to catch up to the thieves, the PCs reached the roof and activated the sky chariot which flew by tossing fireballs in rapid sequence against a pusher plate. A project Orion sky chariot, but using fireballs if you will.
  • The gungineer Ilya took the controls, everyone else strapped in and swallowed hard … the criticality die was at 7. Whatever Ilya did, there was a 35% chance of critical failure inside a sky chariot powered by a lot of fireballs …
  • And Ilya rolled a natural 20 and the PCs escaped with the brother.


The part that really wrapped up the one-shot with a bow was an aftermath I had prepared for the adventure, depending on outcomes.

Spoiler Warning.

The following text of the Aftermath is barely legible. Only read it if you want to know the different ways things could play out.

I’ll leave it unknown what exactly happened in our game.

If Idrargo is killed and the Silverwater is destroyed … the fallen towns decline, most are abandoned, and the fog of forgetting descends.

If Idrargo is killed … a vulpen grickle warlord seizes the Silverwater and carves out a ruthless, man-eating empire. Most of the fallen towns decline. The fog of forgetting mercifully descends.

If Idrargo lives but the Silverwater is destroyed … Idrargo journeys to a town on a river, where he has himself acclaimed a god, and creates an industrial cult of sacrifice to sustain his life.

If Idrargo is left alive … he does not pursue the ones who stole his sacrifice. Nightmares haunt them after, but whether these are curses or not, they do not know. When they die, Idrargo comes to their funeral and watches, smiling.

If Idrargo is left alive … he does not pursue the thieves, but any item they stole slowly eats their memories of the silver ship and what they did, until they only remember that the item was a gift from Idrargo. When they are dying, Idrargo comes to their bedside and they gratefully return his ‘gift’. In exchange, Idrargo gives them a painless and gentle passing.

If Khal is brought back to Elle, she showers the swell-swords in gifts. Khal is more grudging with his remuneration. Roll d6:

(1–3) within a few weeks, Khal’s plotting is again uncovered. This time he is executed. Roll d6: (1–2) and Elle with him, (3–4) but Elle flees along with her iron house, (5–6) but Elle raises a successful rebellion and takes over New Increase.

(4–5) Khal’s plot is successful and he kills Wit “Chasefolk”. This triggers a bitter civil war in the city. It ends with (roll d6): (1–2) the city abandoned after one faction unleashes an ur-plague, (3–4) the city is taken over by an even more ruthless warlord (1-in-6 chance this is Elle), (5–6) with no faction able to claim dominance, they agree to form a republic, which—surprisingly—becomes a lasting beacon of stability on the Lapiz Bay.

(6) Khal’s plot is successful. The initial, romantic springtime of the revolution quickly descends into bloody terror, repressions, and eventually the episode known to history as Khal’s Great Culling.

If Khal dies, Elle blames the swell-sword. Though she pays them as agreed, if they stay in town for more than a day, she sends iron house guards to kill them. As it is, a few months after Khal’s death, Elle’s assassins come hunting for the swell-swords. A few years later she tries again.

Per the Usual

I’m going to definitely try and turn this little one-shot into a zine. It was just so so so much fun to run.

Honestly, I think the two best things were the chief antagonists (especially Khal the Bomberman and Idrargo the Deathless Wizard, but also Elle the Mistress of the Iron House and Wit the Elected Warlord — though his role was mostly ceremonial).

I’m not in the habit of rating my own sessions, but this one … this one worked beautifully. I felt the post-session buzz for nearly 24 hours and … wow. The players really brought it to life in such an amazing, unpredictable way (truth be told, I improvised the sky chariot from scratch).

Five out of five deathless wizards, if I do boast myself.

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