Set in the period before and after the founding of PRC, it is a story that follows the first generation of People's Public Security. CCP undercover agent, Zheng Chao Yang, engages in a battle of wits and will against KMT operatives. Before the battle of Liaoshen, Communist operative CCP undercover agent, Zheng Chao Yang (Zhang Yi), infiltrates and lurks in the Peiping police station. Zheng Chao Yang's identity is discovered by a traitor, forcing him to evacuate the police station immediately. In his escape, he is able to take with him a secret list of KMT spies that can deal a detrimental blow to the KMT. After the liberation of Peiping, Zheng Chao Yang returns to the city. However, waiting for him is a new battlefield. The KMT has dispatched a team of elite spies operating under the codename "Tao Yuan". Tao Yuan is led by the elite spy codenamed "Phoenix" and who is actually Chao Yang's older brother, Zheng Chao Shan (Huang Zhizhong), who is a famous doctor..