Clinical psychologist Ling counsels patient Wei Yin. Wei Yin sometimes expresses that her incompetence has brought regrets to her life and that she is being haunted by her other self. At other times, she is full of confidence and says that she has killed her other incompetent self. However, during the counseling process, Wei Yin suddenly asks about Ling's daughter. Ling is surprised by how Wei Yin knows her daughter's name. She feels that her and her daughter's safety is threatened, and it slowly arouses the regretful memories that had been hidden in her heart for many years.