Five years ago, a fire took the life of Professor Poon, and the notebook on his research for a cure to a deadly disease disappeared without a trace. His assistant Gao Yu (Zhang Jingchu) was saved from a fiery death thanks to the quick action of Chong Tin-po (Daniel Wu), a security guard at the lab.
Now the chief security officer at a top level medical facility, Tin-po protects the lab where Yu works, hoping she will find the cure to the disease that took the life of his wife years earlier. Tin-po is soon caught in an explosive battle when Poon Chi-man (Zhang Ruoyun), a young thief with a mysterious past, steals the curative medicine. After discovering the true origins of the medicine, Tin-po must decide who he can trust to protect the cure from falling into the wrong hands: Poon Chi-man and his accomplices or Tong (Fan Guangyao), the ruthless businessman who funds the facility?