At an Air Force base in Alaska, expert pilot Col. Jim Shannon receives word from dispatch that a Russian plane is circling overhead. He orders Maj. Rexford to escort the plane down without injury, and once it has landed, is shocked to discover that the pilot is beautiful young Soviet lieutenant Anna Marladovna. In almost perfect English, Anna, insisting that she be treated with respect, states that she has defected because she fears she will be killed for disobeying orders. Jim does not believe her, but after she asks to shower and begins to remove her clothes in front of him, grows fascinated by her. He then escorts Anna to his superior, Maj. Gen. Black, who offers her sanctuary but in return demands facts and figures about Russian operations. She refuses, prompting Black and Maj. Lester Sinclair to order a reluctant Jim to seduce her in order to gain inside information. To this end, Anna is treated as a guest of the Air Force and assigned her own jet. Over the next few days, she and Jim impress each other with their skilled flying, and with each question she asks, he deduces more about how the Russians fly and where their expertise is deficient. One night, Anna asks for more training, and in response, Jim kisses her and whisks her off to Palm Springs, California, for a weekend trip. There, she becomes enthralled by what she deems “capitalist luxuries” such as steaks, lingerie and large hotel rooms. At night, Jim and Anna kiss again, and agree that they find each other attractive in every way except politically. When they meet up with Rexford and his wife Georgie, however, Anna invites them and another young couple to share her and Jim’s room. Jim is annoyed, but he soon receives word that Anna is about to be deported, and rushes her out of the hotel. As they fly side-by-side in their jets, Anna radios to Jim that she does not want to leave America, and he decides to marry her in order to save her from deportation. When the happily married couple returns, however, Black takes Jim aside and informs him that Anna is actually a spy named is Olga Orliev, and he and Jim devise a secret plan to have her bring Jim back to Russia where he can spy on the Soviets. Jim returns to their hotel room and plays Anna a recording of her revealing secrets to a Russian agent, and although she fears Jim will kill her now that he knows she is a spy, he confesses that he still loves her. They enjoy several more days of romance, and then Jim tells Anna that he has been reprimanded and that she is to be jailed, then deported. While Black watches from the command post, Jim and Anna sneak onto jets and fly back to her station in Siberia. There, her commander, Vassily Sokolov, places them in separate bunks and subjects Jim to questioning each day. When he deduces that Jim is only giving information that the Russians already have access to, he orders Anna to convince Jim to fly their newest fighter jets. Knowing the jets are unsafe, Anna tries to object, but threatened with a transfer, she visits Jim at night to seduce him into complying. She tells him she loves him, and although he does not believe her, he agrees to fly the fighter. Moments later, he reveals that his agreement does not matter, since the fighter is already outdated, and responds to her outrage by ripping her clothes and locking her outside, half naked. Finally, he lets her in and they share another night of passion. Later, however, she finds a matchbox on which he has been making notes, and realizes that he is figuring out, from Sokolov’s questions, what data the Russians lack. Anna is furious that Jim has lied to her, especially after he assures her that she will help him escape. Instead, she threatens to turn him in, after which the Russians will use him as a double agent. After he demands to know if she loves him, she leaves without responding. When she calls Gen. Dmitri Langrad to inform on Jim, however, she finds that she cannot betray him, and later worries that he will be hurt while flying the fighter jet. Just as he boards the jet, she learns from Col. Matoff that they have been secretly feeding Jim a memory-impairing drug and now plan to administer a huge dose, which will destroy his mind. To save him, she eludes a guard who has been assigned to watch her, and then jumps into a jet. She flies near him and radios for him to follow her, shooting down Russian planes to protect him. Chased by more planes, together they fly to safety and land near the American embassy in Vienna. Weeks later in Palm Springs, Anna declares that she prefers steak to Communist ideology.