Shuu and Haruka are a loving couple facing intense family pressure to conceive a child. However, Shuu struggles with sexual intimacy, making their attempts to have a baby feel like a mandatory chore rather than an act of love. After a medical exam reveals no physical issues, the emotional toll and guilt become unbearable for Shuu. In a desperate bid to ensure Haruka gets the child she desires, Shuu makes the shocking proposal that she sleep with another man.
Shu reveals a shocking secret to Haruka: he can only achieve arousal if she sleeps with another man. Despite her initial horror, Haruka agrees to the request and finds a respectable married man to seduce while Shu listens in via a hidden microphone. The encounter triggers an intense sexual reaction in Shu, leading the couple to feel a paradoxical sense of deep connection through their shared transgression.