Kagerota is a young ninja who embarks on his first mission: stealing the goldfish from a wealthy samurai. He succeeds, but then a mysterious fat cat starts following him. His distinctive red nose leads Kagerota to believe that the feline stalker is actually the reincarnation of his long last father, a legendary ninja who left him when he was ten years old.

Izumi Hoshi is senior in high school, but she led a small yakuza group in her past. After killing her uncle's murderer with a machine gun, her yakuza group disbanded. Izumi now lives an ordinary life as a high school student and works as a manager at a cafe. A dangerous situation soon awaits for Izumi.