Wealthy, retired financier Arthur Goldman resides in an expansive Manhattan penthouse, tended to by loyal secretary, Charlie Cohen, and African American assistant and chauffer, Jack Arnold, both of whom are used to Arthur’s mercurial temperament and eccentricities. In addition to Charlie’s many duties overseeing Arthur’s investments and lavish art collection, he transcribes Arthur’s memoirs about creating some of the best known buildings in New York City. One afternoon, on Arthur’s orders, Charlie takes a metal box from the vault in the apartment and is stunned to find two million dollars in cash. Amused, Arthur then instructs Charlie to read a poem also in the metal box, which echoes Arthur’s earlier observation that the Pope has forgiven the Jews for their role in the death of Jesus. On another afternoon, Arthur dictates more of his memoir to Charlie outside on the terrace, which is decorated with numerous valuable bronze and marble art pieces as well as the elaborate urn holding the remains of Arthur’s late wife. Peering down into the street with a high powered telescope, Arthur grows frantic when he sees an elderly Orthodox Jew pushing a cart along the street. Demanding a stiff drink from Jack, Arthur insists that he has seen his father, then asks why the men do not contradict him when they know that his father died in the Auschwitz death camp during the Second World War. Calming down after taking a sip of bourbon, Arthur resumes his spying on the streets below only to collapse when he sees an SS officer at a hot dog stand. That evening, Arthur’s private physician, Dr. Weisburger, visits while at Arthur’s behest, Charlie dutifully sings to him in German. Pointing out a blue Mercedes parked on the street below, Arthur insists that he is under surveillance, then mentions concentration camp commander, Colonel Karl Adolf Dorff. Going inside with Weisburger and Charlie to watch a televised football game, Arthur mimics Adolf Hitler’s speaking style. Sensing Charlie’s unease, Arthur suddenly berates him for knowing Yiddish but being too embarrassed to speak it, then proceeds to denigrate Jewish communities that were once scattered throughout Eastern Europe and Russia. Although Weisburger is amused by Arthur’s tirade, Charlie remains discomfited. The following morning while Jack arranges breakfast, Arthur slips inside a secret room which is double locked. Jack and Charlie speculate that the room holds valuables or something related to Arthur’s wife. During breakfast, after a wrong number phone call upsets Arthur, he orders Charlie to send specific x-rays to a dentist in Munich and other x-rays to a physician in Argentina along with money taken from an account not in Arthur's name. Accustomed to his employer’s unusual requests, Charlie does as he is bid without question. Later, Arthur is suspicious of a visiting tailor, Rudin, who Charlie assures him, is his cousin. Nevertheless, Arthur waves a Lugar pistol at Rudin, before placing an order for a new robe. The following morning, Arthur asks Charlie about his membership in the building’s health club, but when Charlie says the club would consider it an honor if he joined, Arthur slaps him. Later while walking to the club, Arthur offers a weak apology, claiming that he could not resist the impulse. While working out, Arthur looks out the window and sees the same blue Mercedes parked on the street and startles Charlie by uttering “Arbeit macht frei,” or “work will set you free,” the slogan used by the Nazis on many concentration camp entrance gates. Arthur then abruptly asks Charlie to arrange a private party that evening, with all his female acquaintances. At dinner, his female guests are variously concerned, bemused and skeptical of Arthur’s claim to be leaving soon on a mysterious trip. Concerned when Arthur purposely injures himself after the dinner, Charlie summons Weisburger who demands to know what happened. Arthur insists that Dorff mugged him and when Weisburger expresses confusion, he explains that Dorff wants to become Arthur and warns the doctor not to get “sucked into the logic of the mad.” After the others depart, Arthur sneaks into his secret room, which is bare save for a metal shelf holding decade’s old striped camp uniforms, shoes, glasses and religious paraphernalia from liberated concentration camps. Donning a yarmulke, Arthur opens a large trunk that holds stacks of photos of the bodies of camp victims. Lighting a couple of candles which he places in a menorah, Arthur puts several pictures on the trunk top, then intentionally burns himself under his left arm. A few days later, Charlie reports in alarm that he has confirmed the blue Mercedes is continually parked outside their building, but protests when Arthur instructs him to bring up the car’s occupants. When Charlie nervously enquires if the car’s occupants are German, Arthur replies that they are Centurions sent to arrest him in the garden. While waiting, Arthur turns on a tape of Nazi parade music. Minutes later, several armed men burst into the apartment with Charlie, who is astonished when Arthur allows himself to be strip searched and agrees that the burn under his arm was an attempt to remove an SS identity tattoo. Baffled when the men, Israeli agents, accuse Arthur of being Karl Dorff, Charlie insists that Arthur is sick. A few days later in an Israeli prison cell, Arthur cheerfully welcomes prosecutor Miriam Rosen, who is to prosecute him as former Nazi concentration camp commander Karl Dorff for crimes against the Jewish people. Arthur refuses representation, claiming the Nazis did not murder anyone illegally, but were following their own laws of the time. Noting that the American press has covered his abduction and that the government is demanding his return, Arthur offers to make a deal with the Israeli court. Miriam agrees to hear the request and Arthur states that he will admit that he entered America with a false identity, thus giving up his protection, if the Israeli court will allow him to attend the trail in a Nazi uniform, be addressed by rank and grant him authority to question all witnesses. Without further comment, Miriam agrees to present his request to the authorities. Soon after, psychiatrist Dr. Churchill examines Arthur and concludes that he is psychotic, prompting Arthur to observes that if he is psychotic, so are the multitudes of anti-Semites. Later, Miriam returns with a written agreement to Arthur’s demands which he signs and asks to be made public. When Miriam asks if he killed Arthur Goldman, Arthur replies that he has dedicated his life to him and that he intends the trial to expose the hypocrisy of the Jews. Before Miriam can respond, Arthur insists that mankind only feels alive when killing and that the world hates victims. The following day Arthur appears in court wearing a Nazi colonel’s uniform and finds in place of the usual dock, a glass booth. The presiding judge explains that the booth is to protect Arthur, and is equipped with a microphone and headphones. Admonishing Arthur that he will turn off the microphone should Arthur make irrelevant comments, the judge orders him into the booth. Miriam presents the prosecution's justification for pursuing Dorff thirty years after the events in question with precedents set by the Nuremberg trials and with an appeal to moral law in support of Israel’s actions. Requesting permission to respond, Arthur points out that Israel bypassed international law by abducting rather than arresting him. Miriam responds that one action was not possible without the other. The first witness, Carolotta Levy, indentifies Arthur as Dorff, an officer in Mauthausen camp in Linz, Austria, at the time when she was a prisoner there. After Mrs. Levy describes the inmates’ brutal work of carrying slabs of rock back and forth in a quarry for no apparent purpose, Miriam asks Arthur the reason for the exercise. Arthur agrees that it served no substantive function, but when he blithely adds that it eventually became cheaper and simpler to kill inmates outright, a brief uproar ensues in the courtroom when several spectators rush the booth to attack Arthur. After order has been reestablished, the next witness, Joachim Berger, a German photographer, describes Dorff ordering him to record the gruesome murders of various Polish Jewish men and the responses of their families afterward. Arthur explains that the films served as a legitimate tool to threaten others in occupied countries and puckishly adds that the material suggested an insurgency, which necessitated a counter-insurgency, keeping the officers involved away from the battle front. Miriam then tells the court that they scoured the world to find one person to speak for Dorff and could find only one: Charlie Cohn. Arthur listens with initial delight as Charlie states that he cannot defend Dorff and cannot accept the inhumane treatment in the camps. He concludes that Arthur is not Dorff, but a Jew. When Miriam asks Arthur if he is Jewish, he describes a wartime execution of a large group of Jews who cooperated fully, “quiet as sheep,” and demands to know how he could be a Jew. The next witness, Samuel Weinberg, asserts that on the camp train station platform, Dorff ordered four Orthodox men shot and four others to urinate on the bodies, and says one man died rather than do so. Angrily demanding that Weinberg not make a hero out of that man, Arthur bursts into a tirade which the judge silences by switching off the microphone. The judge asks Weinberg what he thought was happening to other Jews who disappeared from his city, but Weinberg insists that they could never be certain what was occurring. This doubt led many to refuse resisting their German captors, believing if they cooperated they might be spared. As Arthur continues to rave and rap on the glass booth for attention, Miriam declares that never more will Jews be “pushed into the sea,” but they will attack and protect themselves, which brings applause from the spectators. The judge reproves Miriam for being out of order and when he restores Arthur’s microphone, Arthur praises her, agreeing that humiliation was a vital part in the Nazis controlling their Jewish prisoners. Arthur then goes into a lengthy diatribe explaining that Germans acted not out of hate for Jews, but out of love for Hitler. When the judge dryly suggests that some Germans must have disagreed with Hitler, Arthur remains too spent to respond. Miriam next summons German dentist Dr. Schmidt, who compares his dental x-rays of Dorff with those taken from Arthur a week earlier and agrees that they are identical. Next, Argentinean physician Dr. Alvarez confirms that x-rays from his office and those taken of Arthur a week earlier are identical. When Alvarez refuses to acknowledge that Arthur is Dorff, however, Miriam presses him and the doctor admits that as a Jew he cannot lie further. Alvarez then admits that he received the x-rays from a man who paid him. Furious, Miriam recalls Schmidt who initially refuses to retake the stand, who also acknowledges that he too was paid to state that Arthur is Dorff. Exasperated, Miriam presents the x-rays to the judge and declares that the only thing they prove is that the man in the glass booth is Arthur Goldman. The judge asks Arthur why he has chosen to degrade and take blame upon himself, but Arthur does not respond. Peering at him through the glass, Dr. Churchill says Arthur is catatonic. When the judge orders Arthur removed from the booth, he is moved a few feet away before he grabs the keys and locks himself inside the booth. Arthur peels off the colonel’s jacket and, as the sound of gunshots echo in his head, he sprawls against the glass booth. After a moment of shocked silence, the judge begins to recite the Kaddish prayer.