A schoolgirl, Aoi, visits the home of her shut-in classmate, Kenichi. She is forced by her teacher to deliver some papers that were on Kenichi's desk, since his house is nearby. However, the person who greets her is a man named Kenta, who claims to be Kenichi's father. Kenta calls his son a "bad kid." Angered by his words, Aoi ignores Kenta's pleas to stop her and enters Kenichi's room. As soon as Kenichi sees Aoi, he pins her down. Then the man in the room and Kenta join in...