In the distant future, an event called the Quiet Rapture causes all stars and planets to mysteriously vanish, with only those on space stations and spaceships remaining; the human population is reduced to very few.
Simon, a convict imprisoned for his involvement in the destruction of a space station, is forced into piloting a ramshackle submarine, nicknamed the "Iron Lung", sent to explore a moon covered in an ocean of blood; Simon is told that if he completes this mission, he will be freed.