Marina Antonovna, a Soviet spy, and Mateo Arcusa, an American homicide lieutenant first meet in Cambodia during the Vietnam War as enemies. Fearful that the most powerful man in the Soviet Union, KGB Chairman Vladimir Kurenkov, has ordered her death, Marina risks everything to defect to the United States. She promises Mateo that her days as an assassin are over. Vladimir is determined to do whatever it takes to bring her back and, by threatening Mateo's life, forces Marina to break her promise.