Gibo no Toiki

Following his mother's passing, Kaito's father remarries, introducing the young man to his new stepmother, Sayoko. Kaito develops an intense attraction to her. This obsession leads him to spy on Sayoko and later to enter her room at night for sexual contact. Initially guilt-ridden, Sayoko gradually becomes a willing partner. Their secret relationship intensifies after Kaito reveals that his father is having an affair with a younger woman. The ensuing acts of infidelity and betrayal create significant turmoil within the household.