Synopsis
The death of his good friend, police detective Louie Lepetino, brings John "Kit" McKitrick to New York City. Kit, a veteran of the Spanish Civil War, had been convalescing in Arizona after escaping from a Fascist prisoner-of-war camp in Spain. When the train stops in New York, Kit notices a beautiful woman passenger who, he later discovers, slipped something into his pocket. At police headquarters, Kit accuses Inspector Tobin, the head of homicide, of covering up the true cause of Louie's death, which the police have designated a suicide. After leaving police headquarters, Kit visits his friend, Ab Parker, who invites the veteran to stay at his apartment while he travels to Washington, D. C. to work as a decoder. Kit tells Ab of the two years of torture he suffered at the hands of an unseen tormentor, whom Kit knew only by the sound of his dragging foot. Kit tells Ab that he owes Louie his life for arranging his escape, and vows to find his friend's murderer to repay the debt. That night, Ab and Kit attend a party at the house of Barby Taviton, Kit's former girl friend and a patron of the refugee community. At Barby's party, Kit meets Otto Skaas and his uncle, Dr. Skaas, a crippled Norwegian historian who is studying different methods of torture. Dr. Skaas' description of the techniques of mental torture stirs Kit's memories. When Ab tells Kit that the Skaases were present at the party during which Louie fell to his death from an open window, Kit asks for more details and Ab suggests that he question his cousin, Whitney Hamilton, who was also at the party. Later, Kit sees Otto dancing with the woman from the train, whom he learns is Toni Donne, the granddaughter of Prince Francois St. Louis. After Barby informs Kit that she plans to go skiing with Otto, he and Whitney leave the party and go to the nightclub, where Whitney works as a singer. There, Whitney tells Kit that she suspects the Skaases are German agents. Whitney also informs Kit that Otto was in his room changing his shirt during the time of Louie's death and that Toni was the only eyewitness to Louie's fall. After Ab leaves for Washington, Kit returns to the apartment where Ramon, Ab's butler, has unpacked Kit's bags. When Kit opens his suitcase, he notices that the lining has been slit, and later, he finds Louie's badge in his suitcoat pocket and inside its case, the plea for help that he had sent to Louie. The letter triggers Kit's memories, and he listens in terror to the sound of a man dragging his foot while walking. The next day, Kit visits the hat store in which Toni works as a salesgirl, but Toni is rude to him and rejects his invitation to lunch. After leaving the hat store, Kit visits Whitney's apartment to question her about Anton, her refugee accompanist. When Whitney leaves for work, Kit is again haunted by the sounds of a lame man, and he hides under the stairway outside the building to catch a glimpse of the man. Upon seeing the man ascend the stairs, Kit climbs the fire escape into Whitney's apartment. Safe inside the apartment, Kit relates his ordeal and tells Whitney that the man with the bad foot is following him because Kit has something the man wants. The next morning, Toni calls Kit to apologize for her uncivility and invites him to the house to meet Prince Francois. That evening, Kit is greeted by the prince and his houseguests, the Skaases. The prince shows Kit his family banners, which, he explains, represent honor in the traditions of the old world. The prince then proposes that they drink a toast from a set of goblets bearing a medallion of the Lion of San Rafael. Later, Toni warns Kit that he is being watched and asks him to trust her. After dinner, Kit returns to Ab's apartment, where a man attacks him. After overpowering his assailant, Kit turns on the light and discovers Anton. Anton refuses to answer Kit's questions, but informs him that he was allowed to escape so that his captors could follow him to the hiding place of his brigade's flag. Kit then orders both Roman and Anton to leave the apartment. Alone, Kit hears the limping man in the hallway and is about to turn to drink, but resolves instead to be strong and bring Louie's killer to justice. Later that evening, Kit is awakened by the sound of a gunshot and finds Ab shot dead on the floor. After calling Whitney to the apartment, Kit visits Louie's parents' house, where he retrieves a souvenir that he had sent from Spain. He then returns to the apartment where Inspector Tobin is investigating Ab's murder. When Kit informs the inspector that he believes the Skaases were involved in Ab's murder and then tells him about the lame man, Tobin thinks that he is crazy and labels Ab's death a suicide, even though Ab was terrified of guns. Kit then pries open the souvenir case, which holds a medallion of the Lion of San Rafael, the medallion that was attached to his brigade's flag. When Kit gives the medallion to Toni and insists that she wear it, she again warns him of danger, and the two profess their love for each other. Tobin, impressed by Kit's tenacity, finally admits that he believes his story and apprises him that Louie, who was on the trail of an espionage ring, did not fall to his death, but was shot between the eyes and then pushed from a window in the Skaases' room. Kit then explains the signifigance of the flag: Kit's brigade had killed a close friend of the lame man, who then swore to kill every member of the outfit and capture its flag. After Kit leaves the police station, Toni meets him and tells him that Otto shot Louie because he was close to exposing the espionage ring. When Toni begs Kit to give up the flag, he declares that he cannot because it has become a symbol of his batallion's annihilation. Kit then pleads with Toni to go away with him, and she replies that she will give him her answer at the house that night. That evening, Kit is driven to the prince's house by a plainclothes police officer, who waits outside for him. At the house, Kit is greeted by Dr. Skaas, who offers him a drink from the goblets. As the guests are entertained by a Spanish dancer, Kit climbs the stairs to the Skaases' room. As he begins to search the room, Kit hears the sound of the lame man and Dr. Skaas appears in the doorway. Although Kit has a gun, Dr. Skaas accuses him of being too cowardly to shoot and then admits to killing Ab. After Skaas informs Kit that he drugged his drink, he readies an injection of truth serum to administer to him. As Kit collapses from the drug, he shoots Dr. Skaas and calls to his waiting driver for help. The driver comes to Kit's rescue, and over the wail of approaching police sirens, Toni tells Kit that she was married to the real Otto Skaas, who was killed in a concentration camp. When Toni explains that she was forced to cooperate with the spies because the Nazis are holding her daughter hostage, Kit promises to protect the girl and instructs Toni to run out the back door and meet him later at a hotel in Chicago. When Tobin arrives, Kit informs him that the man calling himself Dr. Skaas was really the head of the espionage ring and asks the detective to drop his pursuit of Toni. Kit has hidden the flag in Lisbon, and as he waits to fly to Portugal and retrieve it, he sees Toni board the plane. Accompanied by a police escort, Kit follows her on board and accuses her of being a German spy and lying about having a daughter. After the police escort Toni from the plane, Kit observes that "another sparrow has fallen."
