In the office at midnight, Xia Zilin, a white-collar worker from the company, and her colleagues found a woman lying on the ground. The colleague approached to check, and the woman pounced on her. Xia Zilin escaped for help, but was identified by security as mentally ill. Immediately by the heartDoctor Shen Manni took her to a suburban sanatorium for treatment and met two other pairs of patients who also came for treatment. The problematic father and daughter, Wang Dazheng and Wang Anan, as well as the autistic boy, Azhe, and father, Yan Sikang. Sent within the sanatoriumA series of strange events occurred, and colleagues came to demand Xia Zilin's life. Azhe communicated with the cat demon and Wang Dazheng was entangled by the cat demon. Various suspicious events troubled everyone, and in the end, Shen Manni and herPursuer Qin Haofei solved the mystery one by one using scientific methods.