Na-ra and Yu-jin's usual bickering turns unusually intense. Meanwhile, Young-hoon and Kang go out of their way to impress Won-hee, but their efforts only make her laugh. Young-gyu, who's usually with Mi-ran, visits Na-ra's home alone and surprisingly chooses to stay the night despite his pickiness about sleeping arrangements. Curious and concerned, Na-ra and Yu-jin begin to investigate what might be going on behind his strange behavior.
