What will happen when an extreme soul lives in a person's body? Ma Youxin (played by Wei Shiya) has not received the love of her parents since she was a child. She was bullied by other workers in the garment factory where she worked, but she dared not resist. She often felt that there was a little girl with "Twin" following her. Her mother (played by Wu Wanyi) was very sensitive about this, which made Youxin think that "Twin" was the substitute of her brother who had an accidental miscarriage. Just when the doubts were heavy, Youxin met her sunny and cheerful childhood playmate Shen Xu (played by Alex Lam), and slowly learned to defend herself from him. She secretly made a wish to "Twin" hoping that it would help kill the person who hurt her. Not long after, Shen Xu found the body of Ma's father (played by Ng Man-tat) who had been missing for a long time on the rooftop of the big house; at the same time, the female factory worker who bullied Youxin met with an accident...