Episode 1 recap: A suicide case occurs on campus, and Song Yang becomes a suspect.

In the dark night, the sound of piano playing echoes through the pitch-black campus of South Asia Chinese University. A female college student walks alone near the music room on campus. At the same time, a male student sits on the floor of the library, sketching various shapes of people before their deaths. The area around him is littered with discarded paper balls, as if he has been unable to capture the exact image he imagines in his mind.

The piano abruptly stops playing, and the female student suddenly sees a male student hanging dead in the stairwell. His appearance is strange and terrifying, causing her to scream in shock. The female student's cries alert the security guard, who has been drinking, and he joins her in making a call to the police. Detective Captain Wang Chao and police officer Huang Xiaotao receive the news and rush to the scene with their team. The female student recounts the process of discovering the body. The intoxicated security guard, who is of no help and admits that the surveillance cameras in this area have been broken for a long time, eerily comments that the place is not clean.

Wang Chao and his team only know the deceased's name is Ni Kun; they have no other information. At that moment, they suddenly notice that the lights in the library upstairs are on, but quickly go off again. Acting swiftly, Wang Chao leads his team to surround the young man, who was present near the crime scene. They find numerous sketches of people's appearances at the time of their deaths in his backpack. It is clear that his behavior is far from normal.

During questioning, the young man reveals his name as Song Yang, a college student from a Chinese school in South Asia. While being questioned, Song Yang's phone rings. It turns out to be a call from his uncle, Wang Dali, who sells a product called "Great Power Oil." The conversation between Song Yang and his uncle appears ambiguous, so the police decide to bring them both to the police station. A young boy arrives at the police station looking for his brother, and seeing him triggers memories of Song Yang's own childhood. When he was very young, he learned from his grandfather that he is the descendant of the renowned forensic expert, Song Ci. Under his grandfather's tutelage, Song Yang developed a deep interest in forensic science.

However, when Song Yang was still very young, his grandfather was murdered, and he himself was sent to an orphanage. His grandfather had instructed him not to seek revenge and to live a peaceful and anonymous life. But Song Yang couldn't adhere to that. Another death occurs in the community, as college student Tani has been dead in his bed for seven hours. Someone recognizes him as the person who came to the police station to report a case yesterday. Wang Chao hurriedly returns to investigate the case file. At the time, Tani had reported that a girl named Min Min was killed by him and three others and buried in the mountains. However, today they find the girl appearing fine on campus, and when they went to search the mountains with their companions, the burial site was empty, and their comrade Ni Kun went missing.

The police officers realize that the person he referred to as Min Min is a key witness to Ni Kun's death.