Several years into her marriage, Riho's mother-in-law dies, prompting her father-in-law to stay at the couple's home more often. Riho and her husband keep trying for a baby, but his bland, perfunctory sex leaves her increasingly frustrated. One night after they finish, she secretly masturbates to satisfy herself and is caught by her father-in-law. Seeing straight through her unmet desire, he comes after her, beginning a secret pattern of sex and repeated creampies behind her husband's back.