- During a fight with a gangster, high school student Tsubasa Sato winds up in a prallel world. Tsubasa doesn't understand what is happening around him. After seeing a girl killed in front of him by a pursuer, he finds out that he is now in a world where the lord of the land plays a lethal game of tag - a real onigokko (chasing game) that targets people whose last name is "Sato".
If, during the "game", a target manages to elude his pursuers for a few hours every day for a week, any wish that he has will be granted. When the siren sounds to signify that onigokko has begun, Tsubasa races to protect his sister's double - and hence his sister herself...