Jonah, an unlucky, down-and-out twenty-something, drifts through days marked more by bad luck than by any clear plan. He is bound up in a tense, fragile friendship with Richard, a wealthy man whose charm hides a volatile and controlling streak. One morning, the dynamic erupts in violence: Richard ambushes Jonah and beats him brutally, driven by a paranoid fear that Jonah has slept with his girlfriend, Sasha. Sasha arrives just in time to pull Richard away, explaining that the suspicious texts he found on her phone were not evidence of cheating but plans she and Jonah had hatched to buy him a speargun for his birthday. The admission sows guilt in Richard, and with a hollow apology he invites the two to join him for a day trip on his luxurious yacht, hoping to mend what has become a dangerously radioactive relationship among the three of them.
On the water, the mood briefly steadies as they settle into a fragile calm. But the tension beneath the surface is palpable: Richard’s scrutiny of Sasha fades into the background as the truth of her relationship with Jonah begins to leak into the open. Richard’s anger resurfaces with a quiet, almost clinical precision as he realizes that Sasha has indeed been sleeping with Jonah. His response is swift and dangerous: he trains the speargun on Jonah, a move meant to reclaim control once more. Sasha reacts with a calculated strike from behind, stunning Richard and triggering a brutal struggle. In the chaos, Jonah’s hand is shot by the weapon, the yacht’s radio is wrecked, and Jonah knocks Richard unconscious as the other two scramble to regain control of the situation.
With a grim resolve, Jonah proposes a perilous plan: they should cast Richard overboard and let his death look like an accident. The idea is simple in concept but monstrous in execution, and Richard, when he regains consciousness in the chilly water, claims he nonetheless has the yacht keys in his pocket. He agrees to rejoin the trio if they first dispose of all possible weapons, hoping to prevent any more violence. Back on board, the engine refuses to start, sending the group into a rising storm of anxiety and blame. The argument spirals as Sasha reveals a troubling history: Richard had an affair a year earlier that produced a pregnancy, and the woman involved was murdered soon after. Richard vehemently denies any involvement, but the accusation deepens the rift and casts suspicion on every motive aboard the boat.
Food and water become the new currency of survival. The three discover they have precious little of either, and Sasha, a nurse by trade, bluntly explains the grim arithmetic: without water they will die within seven days. As days slip by, Jonah’s hand infection worsens into a threatening, spreading wound. An ill-fated attempt to amputate the arm by Sasha and Richard only reaches the biceps before they abandon the effort, overwhelmed by fear and lack of proper medical supplies. Starvation and thirst gnaw at them, sharpening every word into a weapon. A brutal calculus settles over the boat: one of them must be sacrificed to save the others. Richard argues that Jonah should be the one given up because his infection is terminal anyway; Jonah, in turn, accuses Richard of continuing the same pattern of betrayals Sasha has endured. The confrontation exposes hidden pasts and present loyalties, and Richard’s anger explodes into a brutal confession: Jonah was the one who murdered the pregnant girl. Jonah does not deny the accusation but instead confesses that the murder was a calculated move to keep the three of them together, to force a sense of precarious unity in the face of their impossible situation.
To decide who will pay the ultimate price, they draw straws. Sasha draws the shortest and, unable to kill herself, prompts a new round of drawing. This time, Jonah pulls the short straw and moves to strike, but instead of killing Sasha, he turns his violence toward Richard, tearing his throat with a broken bottle in a shocking, decisive moment. The power balance shifts in a brutal, instantaneous reversal, and Sasha watches, horrified, as Richard’s life ends in a brutal, intimate act that leaves the deck smeared with blood.
In a final, harrowing twist, Jonah reveals a macabre rationalization that reorients the entire ordeal. While they were discarding weapons overboard at Richard’s insistence, Jonah had secretly removed a fuse from the yacht’s fuse box, ensuring that the boat would be stranded and unable to call for help. He had also hidden away food, crafting a narrative to explain their actions to any authorities: that Richard’s death was a necessity born of their fight for survival. Jonah’s calculated calm gives way to a feverish idea: they could run away together, leaving the wreckage and the law behind. Sasha, gripped by fear for her life, reluctantly accepts the plan as a way to escape the escalating danger. In a final, uneasy move, Jonah re-inserts the fuse, restoring power to the yacht, a fleeting touch of control amid the unravelling.
The end comes with a brutal, fatal echo. Standing at the stern, Jonah is knocked overboard by Sasha in a desperate bid for safety. The propellers do the rest, slicing him apart and leaving only a severed, infected arm to float in the dark wash of the sea. Sasha, driven by fear and a hunger for escape, takes control of the wheel and floors the throttle. The hull roars forward, but the force of acceleration throws her off the side of the boat, and the pilot-less vessel streaks away into the open ocean. The final image is a stark isolation: a single, drifting arm and a boat that no longer has a steering hand, leaving Sasha stranded to confront the vast, merciless sea.
