Yagi Takeru is a student who goes to Izumo Academy. He has no family but he spends his days with his friends like Yamato Takeshi who is his bestfriend aswell as his rival in kendo, Shiratori Kotono and her sister, Asuka.

One day, an abrupt earthquake changed the school completely. The teachers and the students disappeared and the school was infested with monsters. Takeru managed to escape from the school, but he found all his friends and even his town were gone. Then suddently people wearing odd uniforms appeared.

[From AnimeNfo]