On the Jewish holiday Yom Kippur, Thomas Babbington “Babe” Levy, a Columbia University graduate student, runs in New York City’s Central Park. Elsewhere, after removing a Band-aid tin from a security deposit box at a bank, an older German man hands off the tin to a passerby on the street. Driving home, he has a heated argument with another driver, and both cars run into an oil truck, causing an explosion. Later that day, Babe sees a news report about the accident, in which the German man is identified as Klaus Szell, the brother of infamous Nazi, Christian Szell, who was presumed dead after World War II. In a hotel room in Paris, France, a valet attempts to deliver a suit that does not belong to the room’s occupant, Doc Levy. On a phone call to his friend “Janey,” Doc worries that someone besides Janey might know he is there. Doc becomes more suspicious after he delivers a package to LeClerc, a French antique dealer, and detects that LeClerc is surprised to see him. However, LeClerc denies it and promises to have a package for Doc that night at the opera. When Doc leaves in a taxi, a bomb explodes nearby. After showing up late to a seminar, Babe speaks to Professor Biesenthal about his dissertation on the use of tyranny in American political life. Biesenthal says he was once a mentee to Babe’s father, H. V. Levy., and tells Babe that McCarthyism will have to be a focus of his dissertation, even if it was the force that brought his father down, prompting Babe to remember his father’s suicide. Back in Paris, Doc meets his colleague, Peter Janeway, aka “Janey,” for lunch, and announces that someone is trying to kill him. That night, at the opera, Doc finds LeClerc dead and runs away. The next morning, Chen, an assassin, tries to strangle Doc in his hotel room, but Doc overpowers the man and breaks his neck. Doc learns from Janeway that Klaus Szell has died, and deduces that the attack by Chen must be related, saying that they are “getting rid of the couriers.” Meanwhile, Babe meets an attractive girl named Elsa Opel at the library and follows her home. Despite Elsa’s insistence that their relationship cannot go anywhere, she agrees to a date. Sometime later, Babe and Elsa are robbed by two well-dressed muggers in Central Park. On a flight from Uruguay to New York City, Christian Szell disguises himself by shaving the top of his head bald. As Szell’s airplane lands in New York, Karl and Erhard, the men who robbed Babe, are there to meet him. Doc, who is Babe’s older brother, shows up at Babe’s apartment and becomes suspicious when he hears that Babe was robbed by men in suits. Babe asks Doc to take a look at some interviews he has conducted with his father’s old colleagues, but Doc yells at him to forget their father, saying he was a suicidal drunk. The next day, Doc takes Babe and Elsa to lunch, and Babe nervously watches as Doc flirts with Elsa. Catching Elsa in a lie, Doc accuses her of being German instead of Swiss, and suggests she is after Babe for a green card. That night, at a secret rendezvous, Szell admits to Doc that Elsa has been spying on Babe, then stabs Doc in the abdomen. Doc stumbles to Babe’s apartment, bleeding to death, but dies before he can deliver a warning about Szell. Janeway arrives at Babe’s apartment, where police officers address him as commander. Sending the others away, Janeway tells Babe that he suspects Doc’s murder was “political,” having to do with Doc’s line of business. Although Babe believed his brother worked in the oil industry, Janeway reveals that he was an employee of a secret government agency called “The Division.” Later that night, after Janeway has left, Karl and Erhard break into Babe’s apartment, kidnap him, and take him to a secret location. There, Babe is tied to a chair in a sparse room and joined by Szell, who arrives with a set of dental instruments. Szell asks Babe multiple times, “Is it safe?” After Babe responds that he has no idea what Szell is talking about, Szell examines Babe’s teeth with a metal scraper and asks again, “Is it safe?” Babe doesn’t answer, and Szell tortures him with the dental instrument. Later, when Karl moves Babe to another room, Janeway appears and stabs Karl to death. Shooting Erhard as they escape, Janeway takes Babe to his waiting car and drives away, explaining that Karl and Erhard were associated with Szell, the wealthiest and most wanted Nazi alive. He says Szell was a dentist who made money bribing Jewish prisoners for release from Auschwitz, and later invested in gold and diamonds that had been hidden in New York in a safety deposit box. Janeway says that Szell was after Babe because Doc was a courier who transported diamonds to Paris for Szell in exchange for Szell’s cooperation with the Division as an informant. Becoming stern, Janeway orders Babe to confess what Doc has told him about the diamonds, but Babe claims ignorance. Janeway stops the car, and Karl and Erhard approach from outside. Stupefied, Babe cries out that Janeway already killed Karl and Erhard but Janeway admits to using a fake knife and blanks in his gun. Back in Szell’s hideout, Janeway informs Szell that Babe knows nothing, but Szell insists he cannot risk it. In another torture session, Szell wields an electric drill and tells Babe there must be a reason Doc went to his apartment. After Szell drills into one of Babe’s teeth, he determines that Babe knows nothing. Meanwhile, Janeway calls Szell a useless relic and informs him that he must leave the country the next day. When Karl and Erhard force Babe into another car, Babe manages to break away. Using his distance running skills, he outruns Janeway, who hops into Karl and Erhard’s car and directs them toward the highway ramp where Babe has run. Babe jumps from one ramp to another, and an automobile accident stops Janeway’s crew from pursuing him further. Exchanging the Rolex watch that Doc gave him for a taxi ride back to his block, Babe calls Elsa from a payphone and arranges to meet her, then sneaks into a building across the street from his apartment, aware that his building is being watched. In the other apartment building, Babe asks Melendez, a loose acquaintance, to rob his apartment and take his father’s old gun, stashed inside a desk drawer. Melendez agrees, and later breaks into Babe’s apartment with a crew of several men. As Janeway appears and draws a gun, five of Melendez’s men draw their own guns and continue with the robbery. Retrieving the gun from Melendez, Babe meets Elsa and she drives them to a country house. Upon arrival, Babe is suspicious and asks if the house belongs to Szell and if Janeway is inside. Elsa finally admits that Janeway is coming soon and confesses to working as a courier for Szell. When Janeway arrives with Karl and Erhard, Babe holds Elsa hostage, but allows the men to come inside. In the living room, Karl draws his gun unexpectedly and Janeway tries to stop him, but Babe shoots Karl first. Janeway shoots Erhard and Elsa before dropping his own gun, then tells Babe the location of the bank where Szell’s safety deposit box is located. Elsa urges Babe to leave, but as he walks out of the house, Janeway retrieves his gun, shoots Elsa again, and aims at Babe through the window. Babe shoots Janeway first, however, killing him. In Manhattan’s jewelry district, Szell goes to various appraisers to learn the market value of diamonds, but is recognized by one of the appraisers who is a Holocaust survivor. Running away, Szell is recognized on the street by an old lady, another Holocaust survivor, who yells for people to stop him. When the appraiser catches up to him, Szell slits the man’s throat with a switchblade and takes a taxi to his bank. Opening the security deposit box, Szell rejoices at the sight of his massive diamond collection. Leaving the bank with his briefcase full of diamonds, Szell is accosted by Babe, who leads him, at gunpoint, to a water treatment facility in Central Park. There, Babe grabs a handful of diamonds and throws them into the air, telling Szell that he can keep as many diamonds as he can swallow. After swallowing a few, Szell refuses to continue and orders him to shoot. Babe remains frozen, and Szell eventually knocks the gun out of his hand, approaching him with the switchblade. Babe grabs the briefcase and throws it down a set of stairs. Lunging after the diamonds, Szell falls down and accidentally stabs himself, dropping dead into the water. Outside, Babe throws his father’s gun into a lake.