Son's Girlfriend, Daddy's Girlfriend: Dong-gook, who is thinking of remarrying, introduces his stepmother Kyeong-sook to his son Jin-yeong. At the family gathering, Jin-yeong is surprised to see his stepmother's younger brother Hyeon-sook who was his one-night stand just a few days ago! Jin-yeong and his stepmother is lying down, drunk. Meanwhile, there is a strange atmosphere between Dong-gook and Hyeon-sook, who were drinking alone, and at that moment Jin-yeong's girlfriend Joo-yeon appears drunk.