Himari is a married woman who has been married for three years to her husband, who was in the same swimming team as her in school. Due to her husband's injury and marriage, she had stopped swimming, but when a junior student at the same school performed well, she felt nostalgic and visited a swimming class. On the day of the tour, she reunited with her classmate Yamaguchi, who had become a coach. Himari, who had been troubled by her relationship with her husband, was touched by Yamaguchi's consideration and began attending the swimming class. Himari gradually became attracted to Yamaguchi's kindness and strength, and crossed the line of friendship...