One sweltering day, university student Kim Kibum comes home to find Soohyun, a runaway high school girl in front of his house. Trying to be a responsible adult, Kibum attempts to send Soohyun on her on her way. After discovering she may be hiding a painful past not unlike his own, the softhearted Kibum agrees to let her stay. But there's a catch: she must leave in exactly two weeks. The clock ticking, Kibum gets to know Soohyun - only to realize that there might be more to his unwelcome houseguest than what meets the eye…