Baek Sung-soo is a career man with a cleanliness obsession, but one day an unexpected visitor came to the house, and Bai Sung-soo found someone playing a game of hide-and-seek in the room, and his heart ached. Angry, but he couldn't find the place where that person existed. Bai Chengzhu has a beautiful wife and a pair of children. The family lives in a spacious and bright villa, living a contented and happy life. But suddenly one day a phone call broke this happiness. Bai Chengzhu also has an older brother named Bai Chengzhe, who has been missing for three months now. He has not seen anyone alive or dead. Bai Chengzhe's life is far less happy than his younger brother's, and his career is not satisfactory because of the dishonor in his resume. Bai Chengzhu went to his brother's room to find clues, and found that many of the clothes in the room were not his brother's clothes, and the neighbors around seemed to show fear when his brother's name was mentioned. While Bai Chengzhu was investigating the reason for his brother's disappearance, a man on a motorcycle suddenly attacked Bai Chengzhu's wife and children