Giko Nokomura is a female student at Nightingale Academy, who carries around her very own chainsaw. One day she begins to be attacked by modified corpses created by one of her classmates, Nero Aoi . She tears her way through the corpses and busts into Nero's hideout. Why is Nero so intent on attacking Giko?! The reason will shock you!After her battle with Nero, she encounters a new enemy. It's the leader of the Nightingale Academy Student Council Guardians, Nemesis.

There is a schoolgirl who carries her own personal chainsaw. She was attacked by a dead body who was created by her classmate one day. As such, she does not understand why she was attacked by a classmate. To find the answer she ventures into the enemy's base. There she finds out the reason for the assault.