Ippei, an unemployed, middle-aged single man, is a miserable man with neither money nor hope. However, he lives comfortably at his brother Kenichi's house and builds a close relationship with Kenichi's daughter, Waka, Ippei's niece, and is happy because he does lewd things with her almost every day. It all started when Waka came to Ippei for advice about not being able to have sex with her boyfriend. Ippei became aroused by Waka's voluptuous body and performed a fornication on her, saying, "I'll teach you about men." Since then, the two of them find themselves addicted to forbidden acts...