Young man's one-night stand with an older woman leads to complications when she becomes his stepmother after his father starts dating her.

Joon-ha had the best night of his life with an older woman he met while drinking. He starts looking for her as he can't forget the feeling and finally they meet. However, she's going to become his new stepmom. She's his father's girlfriend. When the three start living together, things turn edgy and then dangerous when his father leaves the house one day.