A young couple, Takashi and Machiko, arrive in the bar Quindecim without any recollection of how they got there. The bartender tells them they cannot leave until they first finish playing a game, one in which their lives will be at stake.

College student Shigeru Miura wakes up in Quindecim, and falls in love at first sight with the woman at the bar. Unable to remember even her own name, the woman asks him to play a game with her, after being assured that it will jog her memory.