Childhood friends Mizuki (21) and Sho (25) go to Sho's family home to look for a job. In contrast to her father Kozo (66), who warmly welcomes her, Mizuki learns that her brother Satoru (36) has become a recluse. The next night, while Sho is away, after her interview doesn't go well, Mizuki shares a drink with Kozo. When Mitsuki falls asleep, Kozo carries her to the bedroom and, unable to resist her voluptuous body, rapes her. Her brother Satoru has been watching the whole thing from the darkness.