48-year-old housewife, a company employee living in Yokohama, mother of a 22-year-old daughter. Married for 24 years. She started attending a swimming club six months ago, wanting to cherish her own personal time. She was on the swim team during her school days. One day, she reunites at the club with her ex-boyfriend—her former lover and senior from the swim team. He still maintains his muscular physique and retains his sexual allure. Their first sex in over thirty years delivers an overwhelming shock, making her lose all sense of self. A natural, passionate encounter unfolds, intertwining adult desire with memories of the past.