Every day, Jung-woo goes to a friend's house. In fact, he fell in love with Hyunsoo's mother, Hyunsook. Jin-soo and his lover Nam-joo have to go to a love hotel to have sex in order to live in their parents' homes, and the two people, who are starting to pay the hotel bill, ask Jung-woo to borrow a room for a while.  Jung-woo is in Jin-su's room while the two enjoy sex in her room. Hyun-sook and Jung-woo, who are both under one roof, imagine this and that, and Hyun-sook, who notices their situation, tells Jung-woo that he will go to clean the room.  Hyunsuk came to Jungwoo's room a few days later. I can see the gesture of temptation as she cleans.