Mother's Friends.

Hyeri and Ji-yeon are friends in the same neighborhood. They have a son to go to the army after some time. One day, Min-gu, who was playing at Jun-suk's house, sees Jun-suk's mother Hyeri in the shower and gets excited and hits her. Hyeri, who initially resisted, gave up resistance to Mingu's power, and after that day, the two develop into sex every time they have time. After a few days, Ji-yeon, who accidentally witnessed her son Min-gu and Hye-ri having sex, begins to seduce Hye-ri's son Jun-seok.