Nao, who is sexless and sexually frustrated, distracts herself by throwing herself into housework. Her stepson gazes intently at Nao as she sweats while doing the housework. He masturbates while secretly taking a peek at Nao's bra, which is visible through her sweat, but one day Nao finds him in the act. Meanwhile, Nao can't take her eyes off the young erect penis she accidentally catches a glimpse of. It's been a long time since she's tasted a cock... and before she knows it, Nao is clutching her stepson's penis...