The story starts with a bomber who takes a bus hostage. Aota Pharmacy's representative in Taiwan is apprehended with a bomb while taking a bus hijack, yet dies mysteriously in jail. At the same time, suddenly, mysterious deaths start spreading over one by one. On the other hand, Japanese detective agency "5" received a request by the chairman of Aota Pharmacy. Agent 511 is asked to investigate the company's research development supervisor Taro Kishitani, who has been rumored to have created a deadly virus that can kill at once without leaving any evidence. 511's investigations show that Taro Kishitani, his lover Kumiko and his son have fled to Taiwan. Thus, 511 contacts his old friend in Taiwan, Team Mulan's supervisor - Vice Chief of police Chen Xi and requests his help in investigations. Chen Xi assigns Team Mulan to be in charged of this mission.