- A chemical weapon deal arouses terrorist group Argunbia’s interest, eventually evolving into a theater hostage incident. SDU officers Cheung Ka-hin (Bosco Wong), Ko Chi-lok (Ron Ng) and Yu Hiu-yan (Sisley Choi) are implicated while on leave. They and OCTB Inspector Ho Ka-bo (Jeannie Chan) are stranded at the scene. Read more SDU Chief Commander Fan Siu-fung (Moses Chan) is assigned the task of dealing with the enemy at this critical time. With the assistance of SDU Support Team Leader Cheung Wai-wah (Eddie Cheung), Siu-fung leads SDU to engage the terrorists in a battle of wits and fortitude. The crisis is eventually defused with corresponding internal and external coordination. However, identity of the chemical weapon buyer still cannot be ascertained, and terrorists, who are eager to swing into action, continue to lurk around in the background. Hong Kong faces the most severe security crisis in its history. While on a mission to save hostages in a kidnapping case, SDU is deceived and suffers heavy casualties. Former SDU officer Chin Bok-man (Joe Ma) is appointed as the new Chief Commander. He selects elite officers from SDU and other police departments for organizing a special squad, namely S Team. Faced with looming disasters, S Team collaborate with Interpol officer Hui Chun-fei (Michael Miu) in vigorously preventing toxic biochemical weapons from wreaking havoc in Hong Kong.