Min-goo is troubled seeing her two older sisters, Min-ji and Min-ah, go naked in their daily lives. After much deliberation, he devises a plan to have his friend Byeong-min come into the house. Min-goo proposes a family meeting. He lies to his sisters that he has no time to go because his father's business is not going well and declares that he will bring Byeong-min home. However, her older sister Min-ji is against it... Byeong-min, who entered the house, continues to be driven into a pervert...