Three curious elementary school children, encounter a wanted murderer named "Mr. Sato", who has snuck into an abandoned school they use as a playground to search for a time capsule.
Marika, a high school runaway, wanders into an abandoned house one night and meets a girl with horns. Marika develops a strange affection for this girl and names her "Oni Oni". But suddenly a boy named "Mr. Sato" appears in front of them.
A high school student, Sakuji, loves a beautiful girl named Ayano. So much so, that he repeatedly stalks her on campus. One day, he discovers that there is another stalker named "Sato".