In the post-war era, civilization is rebuilt, and the world is hard to distinguish between black and white. Gu Haitao, an anti-narcotics police officer in planning area No. 7, was assassinated on the night of finding out the truth of the case. Traveling back to three years ago, he no longer trusts his boss who gave the wrong target at the beginning , determined to solve the case independently. However, he was alone and alone, and it was extremely difficult to complete the task. So Gu Haitao decided to make mistakes and use his strength to fight. He was going to rise up in the current undercover circle first, and make up for his injustice to some brothers in the rivers and lakes. Indebted. But in the process, he gradually discovered more and deeper problems...