Bae Suzy has been friends with two handsome guys, Taecyeon and Wooyoung, since childhood. She has a crush on Soo Hyun, a first-year high-schooler, but she has difficulty finding a boyfriend as everyone always wonders about the relationship between Suzy and Taecyeon and Wooyoung. One day, she goes to Taecyeon's house and finds out that Taecyeon has a girlfriend. She is not jealous, but she feels like she has lost him. On the other hand, Taecyeon's girlfriend is upset about how Suzy comes into Taecyeon's room so freely and asks Taecyeon not to let Suzy into his room again. However, Taecyeon disagrees and ends their relationship. Suzy decides to overcome the odds and confesses to her crush. Soo Hyun accepts, but upon finding out that Suzy has a boyfriend, Taecyeon gets upset. On their first date, Suzy finds herself in her room with Soo Hyun. She tells him about something that happened in the past: She once had a chipmunk named Coco, and when it died, Taecyeon and Wooyoung brought her another chipmunk and telling her it was Coco. Her mother had told her to treasure Coco as the two of them had used their own money to buy Suzy another chipmunk. Soo Hyun then shocks Suzy by asking which one of them she likes. After she replies that the one she likes is him, Soo Hyun tries to kiss her but Suzy gets scared. She wants to call for Wooyoung and Taecyeon but she can't. They both suddenly appear after Suzy kicks Soo Hyun away. Of course, she cannot continue dating him after what happened. Although she cant get what Soo Hyun asked out of her head, Suzy is sure that the she will never be anything more than friends with Wooyoung and Taecyeon. But what will happen when Taecyeon confesses his love to Suzy and asks her to go out with him?