Terrorist Jiang Qitai installed a bomb on a subway train and held the mayor hostage, demanding to see Prime Minister Song Il-kwon. Injeong (Bae Doona) is a well-trained female thief who accidentally discovered Jiang Qitai's whereabouts. She informed Officer Zhang (Kim Seok-hoon) of the situation. At the same time, Jiang Qitai's request was not met, and he killed the mayor in anger. The subway loaded with bombs was moving at a high speed in the tunnel, and the safety of Seoul citizens and hundreds of passengers was hanging by a thread. There was a fierce battle between Officer Zhang, who was full of justice, and Jiang Qitai. After that, the defeated Jiang Qitai turned on the countdown switch on the bomb. Knowing that Jiang Qitai had a scandal related to himself in his hands, Song Il-kwon deliberately delayed time in an attempt to destroy the body. On the other side, Officer Zhang was ready to sacrifice himself just to save his beloved woman and the citizens who trusted him.