Ha-ni who was on a honeymoon with her husband, Jae-ho, seems to be uncomfortable with her sister-in-law, Ye-ji. She is a freeloader who lives in her brother’s house without any other job. When the close brother and sister’s affection was being expressed boldly and the sister’s obsession with her brother gets stronger day by day, Ha-ni got tired of her sister-in-law’s behavior of entering their bedroom in her sexy underwear. Ha-ni goes to Ik-tae, the manager of the cabin and had a physical relationship. What could the real purpose of their trip to the mountain be, and what could be the fate of the married couple that is tangled like a thread around Ha-ni and her sister-in-law’s relationship?