In a group photo in the hospital, the ghosts of the first two mentally deceased people appeared inexplicably, causing the whole hospital to panic. After investigation, it was unexpectedly discovered that the initiator was actually Ji Li. Gu Yuan finds the missing Ji Li and finds that Ji Li is an artist with absurd and bizarre style of work, with a strong bloody revenge. Kang Yichen already had feelings for Ji Li at this time. He visited Ji Li despite Gu Yuan's objection, but found that Ji Li didn't know him anymore. At the same time, the patrol found that Ji Li had been sexually assaulted by a patient who had committed suicide. Ji Li became a potential suspect, and Gu Yuan transferred the emotional Kang Yichen from the case. However, another murder, including Chen You, happened. And before they died, they all hummed the same tune. At this time, Ji Li suddenly confessed that she was the murderer of all the cases. On the other hand, Che Suwei and Lu Shijun have a heated relationship, and Li Simin has been following Lu Shijun and assassinating him.