During a routine shipment, the Pony Express freighter spaceship
Tulpar crashes into an asteroid. The crew members (captain Curly, co-pilot Jimmy, medic Anya, mechanic Swansea, and intern Daisuke) survive, but most of the ship's resources are blocked off by airbag-like foam, damage to which could potentially breach the ship's hull and trigger
lethal decompression. Curly, unable to speak or move after being severely mutilated by the crash, is kept sedated via a dwindling supply of painkillers. Declaring himself acting captain, Jimmy accuses Curly of
going postal and causing the crash. When food and medical supplies begin to run low after two months, the crew decide to open their confidential shipment; they discover, to their dismay and confusion, that it consists solely of
mouthwash. A recovering alcoholic, Swansea impulsively breaks his sobriety and consumes the mouthwash for its 14% alcohol content, and his continual intoxication further increases tensions. Jimmy, who has been feeding Curly his pills as Anya cannot bring herself to do so, snaps under pressure and force-feeds Curly in a rage before hallucinating killing him with an axe. Four months after the crash, Anya locks herself in the medical bay with Curly. After failing to convince a drunken Swansea to let them into the utility bay, Jimmy and Daisuke serve him a tainted
mocktail using the ship's sole bottle of
rubbing alcohol. With Swansea rendered unconscious, Jimmy and Daisuke discover that Swansea was guarding the ship's only working
cryopod, which Jimmy believes he was saving for himself. Jimmy coerces Daisuke into crawling through a damaged vent into the medical bay. Daisuke makes it through, but is severely injured in the process. With the rubbing alcohol gone, Jimmy uses the mouthwash as an impromptu
antiseptic, but it only worsens Daisuke's pain. Swansea, having grown fond of Daisuke, reluctantly performs a crude
mercy killing on him with a fire axe. Jimmy goes into the medical bay and it is revealed Anya has committed suicide by overdosing on the remaining painkillers. Jimmy finds the ship's emergency revolver and hallucinates being attacked by a vengeful Swansea. Flashbacks to the days leading up to the crash reveal that the
Tulpar crew were due to be laid off following their delivery due to Pony Express going out of business. At his birthday party, Curly breaks the news prematurely and reveals that due to his service to the company, he has been recommended for a better job. Anya later tells Curly that she is pregnant, hinting that it is the result of Jimmy raping her. Curly attempts to ease tensions with Jimmy, only for Anya to reveal her pregnancy to him behind Curly's back. Curly confronts Jimmy and urges him to take responsibility for his actions. Jimmy warns him that if word gets out about what he did to Anya, Curly will be held accountable as well. This, along with his friendship with Jimmy, results in Curly letting Jimmy go. The stress of his impending layoff, his jealousy toward Curly, and the threat of being held accountable for Anya's pregnancy ultimately drive Jimmy to crash the
Tulpar in a failed
murder-suicide bid; it is revealed that Curly acquired his injuries while attempting to prevent the crash. Jimmy begins to hallucinate that the ship is a maze, finding himself in a graveyard where Swansea hunts him down with a fire axe. He subdues Swansea, who confesses that the years he spent addicted to alcohol were the best of his life, and implies that the cryopod was actually intended for Daisuke. Swansea condemns Jimmy for his selfishness and cowardice, prompting Jimmy to kill him with the revolver. His sanity rapidly declining, Jimmy holds a mock birthday party with Curly and the corpses of the crew. He cuts off and eats part of Curly's leg, then force-feeds Curly his own flesh in a surreal hallucination. He hallucinates himself justifying his actions to his reanimated crew members and apologizing to Curly, who appears to be on fire. After a series of visions in which he is chased by a deformed mass of horse statues, Jimmy finds himself confronted by the Pony Express mascot Polle, who mocks him for his inability to take accountability for his faults. After convincing himself that he can be redeemed if he ensures Curly's survival, Jimmy places Curly in the cryopod, apologizes to him for everything he has done, then kills himself with the revolver. Curly is placed into a 20-year cryosleep, his fate left uncertain. ==Development and release==