Misaki (Shiraishi) has to take care of her only son, Takumi, due to her older sister's transfer. She was dissatisfied with her relationship with her husband, but when she saw Takumi, who was honest and bright, she naturally smiled back. However, behind Misaki's smile, there was a secret that she couldn't even tell her husband. Takumi confides in the secret, and Misaki becomes honest with her feelings, and finally has a relationship with Takumi. Seeking pleasure and knowing forbidden love, a deep groove that cannot be repaired is carved in Misaki's heart!
