Six people find themselves trapped in a mysterious futuristic complex, forced to dance to the tune of a sadistic computer game, where failure to follow the game rules results in death.
Characters include our protanist, Takato Keisuke, his childhood friend Hokari Kanae, classmate Ando Miyako, underclassmate Mikaba Rika, English teacher Aoi Natsuki, same year Byakuya Rinne, and classmate Manaka Nemu.
While still confused about their unusual situation, a mysterious voice suddenly speaks to them: "A game has now started."
In order to escape the room, Keisuke is the "unlocker" and one heroine the "keyhole". With an assigned act, he must "use the key".