Hayase Misako (Oda Mako) is an ordinary housewife who works part-time at a supermarket and lives with her son Satoshi and her devoted husband. One night, a young adult coworker named Kuroki seduces her at a staff party, and she makes a one-night mistake. Although burdened by guilt, Misako cannot forget the sexual pleasure she discovered. She sleeps with Kuroki again and becomes hooked on their intense sex. Then Mamiya (Otonashi Kaori), another part-time coworker who has surrendered to her lust for Kuroki and shaved her pubic hair as proof of submission, appears before Misako...