Wu Fangfang was trapped in the interrogation room. Three of Wu Fangfang's roommates were useless to beat and scold Wu Fangfang. "Yang Yunqing" slaps Wu Fangfang, but in reality Wu Fangfang slaps himself.
Chen Si walked in and asked who Wu Fangfang was. Wu Fangfang followed the tone and expression of her roommate and introduced her multiple personalities, Bai Bing, Fu Xiaohong, Yang Yunqing, and herself. It turned out that Wu Fangfang split into the personality of three roommates and killed Li Guoren, Zheng Tong and Xu Yan at the Fulou Hotel.
From Wu Fangfang's three roommates' personality narration, the tragedy of the 503 bedroom can be vaguely restored. Back then, Bai Bing admired Zheng Tong, the guide of the literary road, but Zheng Tong showed off and shared this love to his brothers Li Guoren and Xu Yan. On the night of the incident, Zheng Tong took Li Guoren and Xu Yan to seduce Bai Bing in the 503 bedroom. Fu Xiaohong and Yang Yunqing rushed to stop him, but they all raped and killed them. Wu Fangfang, who was held in the cabinet by Fu Xiaohong and Yang Yunqing, witnessed the whole process of the case and was frightened crazy.
On behalf of the Jiangcheng Police Department, Yuan Bujie talked to Principal Shi. Principal Shi angrily scolded three former colleagues for killing, and the conversation changed. He hoped that the police department would help to hide the name of specializing when reporting the case. Yuan puzzled directly exposed the embarrassment of President Shi, Zheng Tong, Li Guoren, and Xu Yan, and hid the naked and bloody case. This made the Jiangcheng Police Department find no evidence of the crime in the 503 dormitory. Liu Ziren used luminol reagent on the spot to detect the blood footprints remaining on the ground in Principal Shi's office. Principal Shi argued that Zheng Tong was involved everywhere, and he was afraid that the school would be destroyed. Chen Si and others were not interested in the difficulties of Principal Shi, and directly tortured Principal Shi. The police escorted Principal Shi to Houshan to identify the location of the corpse. The police exhumed the bodies of the three girls who were killed in the 503 dormitory.
The matter hasn't come to an end yet, because Bai Bing and others live in Wu Fangfang's heart, so who is the person who was taken out of the mental hospital. Chen Si and others went to the mental hospital to find Dean He again. Dean He confessed that after contacting Wu Fangfang, he met the personalities of Wu Fangfang's Bai Bing, Fu Xiaohong and Yang Yunqing, and knew the ins and outs of the 503 bedroom. Dean He didn't believe that the Jiangcheng Police Department could convict those three men with the words of a madman, so he secretly visited the three men and knew that they would meet together in Jiangcheng one day each year. Dean He also knew that the girls were trying to kill the three men. Among them, Bai Bing had the most calm personality, so Dean He forged documents and handed over the stabilizer used by the patients to "Bai Bing". Go up, then let her go. Dean He said that he had hesitated before, but he knew that the three men gathered in Jiangcheng to celebrate another year after the incident happened, Dean He made up his mind. Dean He was taken away by the police, and Wu Fangfang returned to the mental hospital again. In the ward, Wu Fangfang faced the personality of three roommates, coexisting peacefully with relief, just like the previous 503 dormitory.
Yuan puzzled lying on the bed and recalled what Master had told him that the water lily of the dream interpreter was not a last resort and could not blossom and switch dreams. Yuan puzzled the water lily carrier on the pocket watch that he had been using for more than ten years. Master didn't expect Yuan puzzled to let go. Now Yuan puzzled because he had vomited blood and attacked his heart because he had opened water lilies many times before solving the case, only then did he understand what Master said.