During the Anti-Japanese War, the Japanese army, aiming to smoothly occupy Changsha, activated a strategic spy known as "Black Butler" who had been undercover in China for 15 years, to carry out a long-planned strategic deception. A Communist Party underground member, Yun Muzhi, was killed in the process of investigating "Black Butler." His son, Yun Hongshen, unknowingly of his father's true identity, pursued the murderer and was caught in a trap already set by "Black Butler." In times of confusion and helplessness, a close friend of his father provided him with significant assistance and protection, allowing him to finally see through the adversary's schemes. Under the leadership of the Communist Party, Yun Hongshen joined forces with the patriotic youth Wen Yeming, setting traps within traps, advancing cautiously, putting aside personal vendettas in the face of national hatred, setting himself up as a sacrifice to uncover the Japanese strategic spies hidden within the Nationalist army, turning the tide of the war, and making a significant contribution to the victory of the first Battle of Changsha.