They wake up in a white room remembering nothing―― The protagonist Takato Keisuke and 6 others are locked up in these hidden white rooms. His 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 ?mystery 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?.