The terrorist Jiang Qitai installed a bomb on a subway train and took the mayor hostage, demanding to see Prime Minister Song Richuan. Ren Jing (played by Bae Doona) is a trained female thief who accidentally discovers Jiang Qitai's whereabouts and reports the situation to Officer Zhang (played by Kim Seok-hoon). Meanwhile, Jiang Qitai's demands are not met, and in his anger, he kills the mayor. The bomb-laden subway rushes through the tunnel, putting the safety of the citizens of Seoul and hundreds of passengers at risk. Officer Zhang, filled with a sense of justice, engages in a fierce battle with Jiang Qitai. After being defeated, Jiang Qitai activates the bomb's countdown switch. Knowing that Jiang Qitai has information related to his own scandal, Song Richuan deliberately delays time, hoping to cover up the evidence. On the other hand, Officer Zhang has already prepared to sacrifice himself, just to save his beloved woman and the citizens who trust him.