A North Korean spy, Cheol-jin, is dispatched to the South to steal a DNA sample of the super pig developed there. However, when Cheol-jin gets in a cab to make contact with the stationed spy, Mr. Oh, he gets robbed of his bag, which holds operational funds and his gun, by a four-man cab robbery team. Cheol-jin eventually makes contact with Mr. Oh but he cannot execute the operation empty-handed so he ends up staying at Mr. Oh's house. Soon after, Cheol-jin gets an order to eliminate a spy who has defected to the South. Following his orders, Cheol-jin goes to eliminate the defected spy but learns that the subject is his closest friend. Having no choice, Cheol-jin kills him. Filled with remorse, guilt and anger, he wants to stop the mission but decides to continue when thinking of his family and countrymen back home who are starving to death. He succeeds in stealing the DNA sample from the laboratory but the following day, he sees a report of the South Korean government deciding to supply the super pig to the North. No longer useful, Cheol-jin is killed by fellow spies as he attempts to return to the North.
