Ayaka has a dear friend named Hiroko. Hiroko suddenly vanishes from Ayakas life, saying that she must save someone important to her. Since that time, Ayaka hasnt heard anything from Hiroko, until a girls corpse is washed up on shore, and shes holding a letter from Hiroko which reads: Come save me. Ayaka sets off to save her best friend, and ends up in a mysterious school where everything seems too good to be true. Is it?