Ji Yeon-hee is an extremely shy, introverted 23-year-old girl with zero dating experience and a tendency to blush when talking to someone she likes. One day, four young men move into the house right next door to Yeon-hee's home, and to her surprise, they turn out to be Chanyeol, D.O, Baekhyun and Sehun from her favorite boy band Exo, who are looking to lay low for a while. They hire her to clean their house part-time during the winter vacation and that's when Yeon-hee found out that Chanyeol was her long lost childhood friend and crush "Chan" and is the grandson of the house owner. As the story goes on, Yeon-hee soon becomes involved in a love triangle with Chanyeol and D.O.