Qi Si is the head of the serious crime team of the Criminal Investigation Detachment. He is cold and sharp, with observation as sharp as a knife. He is accustomed to using the most direct way to reveal the truth. He has top skills, a violent temper, and strong principles. He seems to be unkind, but in fact he is extremely paranoid about justice. He hides an old case that has not been settled for many years, which is a weakness that he dare not touch.
Shen Jin is a criminal psychology consultant specially hired by the city bureau. He is gentle and has an excellent IQ. He can easily see through the darkest folds of the human heart. He seems to be weak and non-aggressive, but he can defeat the murderer's psychological defenses with just one sentence. He has a mysterious background and never mentions the past. There is a depression in his eyes that is inconsistent with his gentle appearance.
One is a sharp blade that charges into battle, and the other is a cold knife that pierces people's hearts. From being dissatisfied with each other, they become the only comrades that each trusts. They stand side by side in serial murders and walk together in the dark abyss.
Purpose: Investigate the case side by side