As the story opens, a Corporal Bower (Ben Foster) and a Lieutenant Payton (Dennis Quaid) wake up from hypersleep aboard the sleeper ship Elysium. The ship is on a mission from an overpopulated Earth to the earth-like extrasolar planet Tanis on a colonizing mission. With no recent memory and the ship racked by power surges from its unstable reactor, Payton sends Bower to stabilise the reactor, since his position and latent memories imply that he is an engineer. While making his way through the ship, Bower finds emaciated corpses and has to avoid strange, pale humanoid beasts who use bladed weapons and lassos to catch and kill their human prey. He also finds several people who had been awake far longer than he and Payton, including a genetic engineer named Nadia (Antje Traue) and an agricultural expert called Manh (Cung Le). During his journey, Bower experiences the physical symptoms of a mental disorder encountered in long periods of space travel, called Pandorum. At one point, Payton tells of a prior case where the captain of a passenger ship went mad with the syndrome and, believing the flight was cursed, ejected all the passengers and himself into space, dooming them all. On the flight deck, Payton discovers another crew member, Corporal Gallo (Cam Gigandet), who reveals that he was part of the flight crew that received a final message from Earth, saying that the planet had been destroyed and the only hope for humanity was the Elysium. He claims that his other two crew mates suffered from an onset of Pandorum, and that he had to kill them in self-defense. Payton is wary of Gallo, noting his strange behavior. It is eventually shown that Gallo has Pandorum and is dangerously insane.