Prot is a patient at a mental hospital who claims to be from a far away planet. His psychiatrist tries to help him, only to begin to doubt his own explanations.

Career criminal Johnny Clay recruits a sharpshooter, a crooked police officer, a bartender and a betting teller named George, among others, for one last job before he goes straight and gets married. But when George tells his restless wife about the scheme to steal millions from the racetrack where he works, she hatches a plot of her own.

After a chaotic night of rioting in a marginal suburb of Paris, three young friends, Vinz, Hubert and Saïd, wander around unoccupied waiting for news about the state of health of a mutual friend who has been seriously injured when confronting the police.

A group of strangers find themselves trapped in a maze-like prison. It soon becomes clear that each of them possesses the peculiar skills necessary to escape, if they don't wind up dead first.

Eight strangers awaken with no memory, in a puzzling cube-shaped room where the laws of physics do not always apply.