Lazy, uninspired, kind, shy, irresponsible, all of these words can describe Izumi Kaivou, a 17 year old boy who resides in modern times on the planet Earth. Living in the city of Hotaru, and attending Gunma High, Kaivou was left with the great responsbility of becoming a parent to his younger sister, following their parents tragic death. But, that hasn't worked out too well, as it is usually his Sister who attends to all of Kaivou's needs, from cooking him dinner, to getting him out of bed in the morning. As more of a follower than a leader, he is often thrust in to some pretty troublesome quests with his best friend Tashiro Yamu, most often dealing with members of the opposite gender. Tormented by bizarre nightmares, Kaivou's apocalyptic premonitions foresee that soon nobodies life will ever be the same again!