The story takes place in the early 1990s. Gu Ming (played by Yu Hewei) was promoted by Wu Jiannan (played by Yao Wu), the director of the Public Security Bureau, to become the captain of the criminal police. As soon as the new official took office, Gu Ming shouted the slogan "The murder case must be solved, and it will not stop until it is solved", and he has been implementing this belief in his subsequent career. However, not long after he took office, a serious homicide occurred in the city. Faced with this case with neither evidence nor clues, the investigation fell into a deadlock, and finally, Gu Ming admitted defeat. Time passed quickly, and Gu Ming relied on his own efforts to fight on the front line, solving countless strange and confusing difficult cases. Fifteen years later, when the relevant clues of the homicide case that once defeated him surfaced again, Gu Ming knew that this was his last chance to redeem his shame.