The relationship between the couple has become cold. The wife, Aika, is feeling increasingly lonely. Without a night with her husband, her skin and excess fat begin to sag as she matures. She secretly buys corrective underwear... One day, she is seen in her underwear by her husband's younger brother, who is much older than her. The brother-in-law cannot contain his excitement at the lewd appearance of his sister-in-law. The two of them indulge in forbidden acts and escalate, despite knowing that their relationship is forbidden.