Otonashi awakens only to learn he is dead. A rifle-toting girl named Yuri explains that they are in the afterlife, and Otonashi realizes the only thing he can remember about himself is his name. Yuri tells him that she leads the Shinda Sekai Sensen (Afterlife Battlefront) and wages war against a girl named Tenshi. Unable to believe Yuri's claims that Tenshi is evil, Otonashi attempts to speak with her, but the encounter doesn't go as he intended. Otonashi decides to join the SSS and battle Tenshi, but he finds himself oddly drawn to her. While trying to regain his memories and understand Tenshi, he gradually unravels the mysteries of the afterlife. 舞台は死後の世界 運命に立ち向かう少年少女たちの物語 なんらかの理由で最後を遂げた少年・音無は、死後の世界の学校で、ゆりと名乗る少女と出会う。 彼女は神に反逆する「死んだ世界戦線」のリーダーで、天使と日夜激戦を繰り広げていた。 そして、立ちはだかるは神の使い・天使。それは、可憐なひとりの少女だった。 生前の記憶が無く、この死後の世界で何が起きているのかも分からず戸惑う音無。 彼は、ゆりたちと共に戦う道を選ぶことにしたのだが…。
