Small-time criminal Carlos comes home to find his younger brother, Oliver, agitated. Before Oliver can explain his behavior, rogue cop Marcos emerges from hiding and places both brothers under arrest. Oliver explains that he has confessed under duress and begs forgiveness. Carlos demands to see a warrant. Marco admits he does not have one and attempts to take them to the police station at gunpoint. They overpower him and flee down their apartment complex's stairs. While chasing them, Marco shoots Carlos in the leg. Marco seems surprised by his action and is further worried when he hears a loud noise in the distance. Carlos and Oliver surrender to Marcos, who refuses to take them to a hospital.

Marco is horrified when the stairs turn out to be endless, looping in on themselves. Oliver applies first aid to his brother but can only watch as Carlos bleeds to death the next day. Before he dies, Carlos urges Oliver to appreciate the present, something he could never do. As Oliver mourns Carlos' death, Marco becomes shaken when he sees that a vending machine on the stairwell has become restocked, exactly as it was 24 hours ago. Enraged by Marco's callousness, Oliver disarms him and threatens to kill him with his pistol. Marco insists that he did not consciously choose to shoot Carlos, and the two argue over the metaphysics of their situation.