A story that follows the first generation of People's Public Security. Zheng Chaoyang engages in a battle of wits and will against Kuomintang operatives even if it is against his own brother.
Before the battle of Liaoshen, Communist operative Zheng Chaoyang (Zhang Yi) who had infiltrated the Beiping police had no choice but to retreat after his identity was discovered. In his escape, he was able to take with him a list that can deal a detrimental blow to the Kuomintang.
After Beiping's liberation, Zheng Chaoyang returns to the city. However, waiting for him is a new battlefield. The Kuomintang has dispatched a team of elite spies operating under codename Taoyuan. At the helm is Zheng Chaoyang's older brother Zheng Chaoshan (Huang Zhizhong) who is a famous doctor.