Ten years ago, his wife passed away, leaving him to raise his beloved daughter alone. With a beautiful face resembling her mother, they had built a warm and loving relationship. One day, the daughter said she would stay overnight at a female friend's house, and from that night onward, her behavior began to change. When the father secretly checked her phone, he found love messages addressed to her. Realizing the truth, he became convinced that his beloved daughter had lost her virginity—and driven to madness, he sets his sights on the one remaining virginity she has left: her anus.