In the land of Eostia, humans and dark elves have fought for supremacy for over a century. The dark elves rule over a race of monsters that has raided human lands for generations, capturing and defiling their women. Aided by powerful bands of mercenaries, the human kingdoms have gradually pushed back their old rivals. But the mercenaries would not settle for these victories. Led by the cruel general Volt, the sellswords declare independence. With the support of the savage orcs, their new nation attacks human and dark elf alike, carving out a kingdom where men reign supreme and women are little more than slaves. Even the dark elves’ castle is conquered and their queen taken prisoner. The sole hope for peace in these lands rests with a fellowship of seven princess knights, handpicked by the goddess of the high elves. But is their power enough to cleanse the evil from their world?

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 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 “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”.