On a cold night, psychology student Liu Kai took Jing Huan, a paranoid schizophrenia patient, to a mysterious frozen lake she had often dreamed of. The lake reflected an “8” shape, causing Jing Huan’s expression to change, unsettling Liu Kai. During an internship at a psychiatric hospital, Liu Kai’s classmate Xie Ni, who was in a relationship with him, became interested in Jing Huan, a former factory cashier who developed mental illness after embezzling funds. Xie Ni wanted to study Jing Huan’s condition for a thesis and asked Liu Kai to help her, even arranging for Jing Huan to stay at her home.