Life and Death. It's nothing but a game.

He thought he was dead. The last thing Kei remembers is the train running over his own body. But now he is in a room filled with strangers, all resurrected by a strange, featureless black sphere known only as the Gantz. Caught in a strange realm between life and death, Kei and the others must undertake brutal missions that the Gantz assigns. Otherwise, none of them will live long enough to leave the room.Is it a game? A nightmare? All Kei knows is that this reprieve from death may only be temporary. If they fail, they will die again..