Sigma, the main character, is kidnapped and awakens in an elevator with a girl named Phi, who seems to know him. Zero III, a talking rabbit, appears on a computer monitor in front of them and tells them they must escape the elevator; the pair find themselves in an abandoned warehouse alongside seven other people. Their goal is to escape the building. However, they find themselves enrolled in a game known as the Nonary Game: Ambidex Edition, which relies on a system called "Bracelet Points" ("BP"), which are won by cooperating with or betraying other players. A player is allowed to leave the warehouse if only they possess nine or more BP; however, if a player's BP reach zero, they are killed by a lethal injection.
Source: Wikipedia, "Zero Escape: Virtue's Last Reward", available under the CC-BY-SA License.