Set around the founding of the PRC, the story follows CCP undercover agent Zheng Chaoyang as he battles KMT operatives. After his cover is blown at the Peiping police station, he escapes with a critical list of KMT spies. Returning to Peiping post-liberation, Chaoyang faces a new challenge—elite KMT spies led by "Phoenix," who is revealed to be his estranged brother, Zheng Chaoshan.