In 228 AD, the Shu army defeated Wei in the Northern Expedition.The intelligence department of Shu analyzed that the false information that led to the Shu army's misjudgment was sent by Chen Gong (actor Chen Kun), a senior spy lurking in Wei.Xun Xu (played by actor Bai Yu), a counter-espionage expert from Shu State, was ordered to sneak into Wei State to investigate Chen Gong.Chen Gong passed Xun Xu's investigation, and they discovered that within the intelligence department of Shu, there had been an undercover Cao Wei agent codenamed “ Zhulong”. “ Zhulong” not only replaced Chen Gong's information, but also prepared to steal the design of the Shu LiannuTu's secret operation launched the “Qingping Plan” to create chaos in Shu.Xunxu returned to Shu and planned to work with Chen Gongli to uncover Zhulong's true body.Xun Xu successfully prevented Wei from stealing Lian Nu's secrets and discovered the traitor hidden in Shu's intelligence department.After Chen Gong ended his undercover career and returned to Shu, he and Xun Xu went through many tests and finally revealed the truth behind Qingping's plan.Faced with the righteousness of their family and country, Xun Xu and Chen Gong made the right decision at the critical juncture, cracked the enemy's sinister plot, and maintained the stability and unity of the country.