In 1948, Yu Beiping, an important official of the Special Investigation Bureau, was transferred to Qingcheng by his superior and was ordered to investigate the murder case that occurred there. In fact, Yu Beiping’s true identity is being investigated and suspected by his superior, and he is in danger all the time. Yu Beiping has to successfully complete the tasks assigned by his superior on one hand, deal with the cunning and insidious enemy on the other hand, and also bear the incomprehension and misunderstanding from his closest relatives. He is in a difficult battle.