Mitsuki (21) and Sho (25), childhood friends, go to Sho's parents' house for job hunting. Mitsuki learns about the reality that her brother, Satoru (36), is a recluse, in contrast to her warmly welcoming father, Kōzō (66). The next night, while Sho is absent, Mitsuki, who didn't do well in her interview, shares a drink with Kōzō. Eventually, Kōzō, who carried the fallen-asleep Mitsuki to the bedroom, couldn't resist her voluptuous body and violates her. Her brother, Satoru, was watching the whole thing from the darkness――.