Xu Sen played by Flying Tigers 3 Liang Liewei is a bad guy. Xu Sen is a doctor of biology who came back from studying abroad and won various awards. But he chose to return to China because he wanted to serve the country and contribute to the domestic medical cause. However, with the development of the plot, all the truth surfaced. It turns out that Xu Sen is a member of the mysterious organization "Infinite Front". He came to Du's company to get the formula of DH2, so as to control and even change the world.

The terrorist organization "Waganbu" infiltrated Hong Kong and launched a battle for chemical weapons in Hong Kong. Fan (Chen Hao), the commander-in-chief of the Flying Tigers, was ordered at the crucial moment to lead the Flying Tigers in a life-and-death struggle with terrorists. The Flying Tigers were trapped in the ruthless killing in Waganbu. The Director of Secret Service Zhan Bowen (Ma Dezhong) called police elites Zhang Weihua (Zhang Zhaohui), Zhang Jiaxuan (Bosco Wong) and Gao Zile (Ng Cheuk Hai) to form a secret anti-terrorism team. Faced with numerous crises, with the assistance of Interpol Xu Junfei (Michael Miu), the younger generation of China and Canada finally put aside their grievances and joined hands to stop the spread of chemical weapons virus in Hong Kong.