After her husband Masahiko suddenly becomes impotent, his wife Miku suffers both emotionally and physically. While Masahiko is at work, she indulges in masturbation using a massager. Unbeknownst to her, a pair of eyes peers through the door crack—her father-in-law, Eiji, who has arrived unannounced. He sneaks into the couple's bedroom and curiously examines Miku's underwear and cosmetics. Knowing the couple's marital relationship has become dysfunctional, Eiji forcibly reaches out to Miku's aching body. Amidst a mix of tension and anxiety, a forbidden relationship begins.