Yūka Tanabe leads a content, ordinary life as a married woman, maintaining a domestic routine of meal preparation and household management while her husband works. Her stable, affectionate marriage, however, is devoid of passionate intimacy, leaving her sexually unfulfilled. She suppresses these feelings to preserve their peace.

This routine shatters when an unknown man assaults her at home. Initially consumed by guilt and viewing the encounter as a betrayal, her resistance gradually fades. She develops a willingness to continue the affair, actively seeking encounters during her husband's absences. The intense physical satisfaction she gains starkly contrasts with her marital experiences.

Yūka navigates a psychological journey, reconciling her persistent guilt with the powerful gratification the affair provides. Indications suggest her husband may possess awareness of her infidelity, intensifying her emotional turmoil. Her story centers on this internal conflict and the consequences unfolding within her marriage.