JUL-396 The obedient wife secretly has an affair with the swimming teacher.

Aoi, a woman who has been married to her husband for three years. Straying from her initial kind heart, she feels lonely in the face of her husband's attitude. While going shopping for dinner with her own worries, she unexpectedly encounters Hosoda, a classmate from her university days. There, she learns that Hosoda is working at a swimming class, and Aoi is invited to visit her and decides to attend her swimming class. Subsequently, every time she goes to the swimming class, Aoi starts to be attracted to Hosoda's kindness, which alleviates the worries about her husband. And on the day her dissatisfaction with her husband explodes, Aoi crosses the line with Hosoda.