Jiyeon finds herself in disbelief after waking up next to someone twelve years younger. As she tries to gather her thoughts, she can't wrap her head around the situation—she just had a one-night stand with a guy who used to be just a kid in her eyes. Five years ago, Minjun, the neighborhood high schooler, confessed his feelings to her, but she didn't take him seriously. Now, he's back, no longer a boy, but a man. After a chance encounter at a bar, Jiyeon reconnects with Minjun, who is now a bartender. As their past connection resurfaces, Jiyeon is torn between the memories of the boy he was and the man he's become. Minjun is determined not to lose her this time, and Jiyeon must come to terms with the fact that he's no longer the playful kid—he's grown up and ready for something real.