A female student, Mitsuki, visits the home of her shut-in classmate, Kenta. However, when she presses the intercom, no one answers. When she puts some papers in the mailbox and is about to leave, a man named Dango appears. Dango introduces himself as Kenta's father and calls his son a "bad brat." Angered by his words, Mitsuki ignores Dango's pleas and enters Kenta's room. As soon as Kenta sees Mitsuki, he pins her down...