"Yuri" has a secret that she cannot tell her husband. It is an encounter with an older man "Kato" who lives in the same apartment next door. The affair starts with a light-heartedness, but eventually becomes an inseparable relationship. "Yuri", who wants to have children while "Kato", who is confused about vaginal ejaculation, probably has a low sense of purity and closes her eyes with a happy expression.