In Dallas, Texas, Walter Lloyd takes his wife, Donna, to the airport, where she is embarking on a long European vacation. She tells Walter to make an effort to reconnect with their young adult son, Chris Lloyd, while she is gone. Chris asks his father why he refused to leave his lumberyard business and go with his mother on vacation, but gets no reply. In time, Walter takes his estranged son on a fishing trip. When they return home, Walter receives a telephone call informing him that his wife went missing from her tour group, and Chris insists they go to Paris, France, to search for her. On the airplane, Chris asks his father if he and his mother are getting along, and wonders aloud if perhaps his mother has met another man. While Chris collects their bags at the airport he meets a beautiful French girl named Carla. Meanwhile, a German man named Hans Henke holds Walter at gunpoint. He shows Walter his wife’s bracelet, and begins leading him out of the airport. However, another man points a gun at Walter, and when Walter pushes a cart into the assassin, Hans Henke is accidentally shot and killed. In the chaos, Walter takes Henke’s gun and wallet, and returns to Chris as if nothing has happened. They settle into their Parisian hotel, and while Chris sleeps, Walter visits the American Consulate, where he sneaks into the office of a man named Ross and orders him to send a message to Ross’s superior, Barney Taber. Referring to himself as “Duke,” Walter reports that his wife has been kidnapped, and gives the name of the hotel where Taber can find him. Sometime later, Walter makes a telephone call and is followed by an unknown man. Walter tells Chris about Hans Henke approaching him at the airport, and reveals that his mother has been kidnapped. As Walter talks to his son, Barney Taber arrives, and Walter introduces him to Chris as an old friend. Taber asks for any information about Walter’s missing wife, and Chris begins to relay the details of his father’s encounter with Hans Henke, but Walter cuts him off. Although Taber only works as a “liaison to the economic commission,” he promises to do everything he can to find Donna Lloyd. After he leaves, Chris questions his father about not revealing everything to Taber, and wonders why Taber called his father “Duke.” Later, Chris overhears his father speaking fluent French, and realizes that his father is leading a double life. Walter receives a telephone call from the kidnappers, and insists that Chris stay behind while he goes to meet them. However, Chris follows him, saving his life when the assassin from the airport shoots at Walter from behind. Walter confesses to Chris that he used to work for the Central Intelligence Agency (CIA), and that someone other than the kidnappers wants to kill him. When someone selling watches approaches, Walter points a gun at the innocent man, and Chris is stunned at his father’s reaction. Chris wants to go to police, but Walter insists they talk to Taber, who works for the CIA. Taber tells Walter to wait at the hotel for the kidnappers to contact him again. However, he and Chris rent an automobile and drive to Hamburg, Germany, to meet with a former contact of Walter’s named Lise. Walter notices they are being followed, and holds the bumbling “shadow” at gunpoint until he admits to being a CIA agent named Mason, sent to protect Walter. Walter threatens Mason, and he and Chris continue on to Germany by train. At the Hamburg train station, a man plays a tune on a violin to get his attention, but Walter eludes the man. Chris sees Carla, the girl he met at the Paris airport, but does not speak to her. They arrive at the home of Walter’s former colleague, Lise, and she and Walter share stories from the past. Chris overhears Lise tell his father that she loved him. Walter tells her that he loves his wife, Donna, but laments not having a second life to share with Lise. The following day, Lise sends Walter to former associate, “the Colonel.” En route, Chris and Walter are again followed by the violin player from the train station. The assassin joins the pursuit, and a car chase ensues. Chris lets Walter out of the automobile, and runs to a bridge. Walter jumps onto a passing riverboat below, and witnesses the assassin shoot the violin player, who appeared to be trying to help Walter. Chris and Walter escape and visit the Colonel, who informs Walter that Hans Henke worked for the German Secret Service, and asks Walter about “Clean Sweep,” his last operation before leaving the CIA. Walter recollects that he was ordered to kill six corrupt German agents, but one, whose name he cannot recall, got away. Sometime later, the family of the sixth man was killed, and Walter denies that his team was responsible for the unauthorized murders. When the Colonel asks what tune the violinist was playing, Walter realizes it was code, and remembers the sixth man’s name was Schroeder. The Colonel asserts that Schroeder has kidnapped Donna Lloyd. Walter travels to West Berlin to pursue Schroeder, and leaves Chris with Lise, where she will send him to stay out of harm’s way with her friend in Frankfurt, Germany. Meanwhile, the assassin tortures the Colonel to get him to reveal Walter’s whereabouts. After the Colonel’s nurse gives up the name of Walter’s hotel, both she and the Colonel are murdered. Waiting for his airplane to Frankfurt, Chris again sees Carla, and decides to go with her to West Berlin. When they arrive, Carla seduces Chris, but he leaves her bed to inform his father that he is in West Berlin. Lise telephones Walter and tells him of the Colonel’s murder, and that Chris failed to arrive in Frankfurt. Chris arrives at his father’s hotel room, and Walter nearly shoots him. He admonishes his son for deviating from the plan, but allows Chris to help him. While Chris sits watch outside the hotel, Carla arrives and surprises him, and confesses she was jealous he was meeting another woman. Chris sees the assassin arrive, but before he can alert his father, Carla points a gun at him. When the assassin enters Walter’s room, Walter kills him. Outside, Chris strikes Carla in the face, and runs to his father’s side. Father and son escape, and Chris is disappointed in himself for falling for Carla’s ruse. Walter consoles him, and tells him the kidnappers might ask him to trade his life for his wife’s return. Chris expresses his love for his father and returns to Paris to wait while Walter meets with Schroeder. Schroeder accuses him of murdering his wife and children, but Walter claims he and his team had nothing to do with their deaths. Walter reveals that he was being pursued by an assassin, and suggests that whoever sent him is behind the murders of Schroeder’s family. He convinces Schroeder to allow him to investigate further before he kills Donna. Walter telephones Chris at CIA headquarters in Paris, where the younger man waits with agents Taber and Clay. Walter instructs Chris to meet him alone at a secret location in West Berlin. Chris arrives, followed by Taber and Clay, and Walter attempts to sort out the past. Chris enters a warehouse and finds his mother tied to a chair, rigged with explosives. They all work to disarm the bombs. When Chris sees one of Schroeder’s men, and is told to keep quiet, he realizes that his father has a plan. Donna is freed at last, and embraces Walter. Walter tells Taber that he is going to turn himself in to Schroeder so he will not have to live as a target for the rest of his life. However, Taber holds Walter at gunpoint, refusing to let him assert his innocence to Schroeder. When Clay questions Taber’s actions, Taber shoots him. Schroeder arrives, and when Taber speaks to him in German, Walter realizes that Taber is a double agent and responsible for murdering Schroeder’s family. Schroeder ties up Taber and instructs Walter to leave with his family. Outside the warehouse, Chris and his parents embrace, as the building explodes.