Maki Hojo and her husband temporarily take in her nephew Shin, who has come to Tokyo for summer classes. One day, Maki discovers Shin masturbating with her underwear. Furious upon realizing he has been secretly recording her, Maki confiscates all his belongings and checks their contents. Watching the footage, she becomes aware that it reflects her own unsatisfying daily life, intensifying her sexual frustration. That night, sneaking into Shin's room, she finds him masturbating again. Saying, "Let me help you," Maki gives in to her desires and begins seducing the young man.