In September 1963, in Israel, agent David Porath learns that Egyptian President Gamal Nasser’s attack plans for Israel need only the completion of a missile tele-guidance system that is being developed in an unknown factory in West Germany under the supervision of an organization known as Odessa. Porath returns to Europe that evening to discover the factory involved and halt the guidance system’s development. In Hamburg in November on the evening of the assassination of U.S. President John F. Kennedy, freelance reporter Peter Miller receives the diary of elderly Salomon Tauber, a recent suicide, from his friend, police inspector Karl Braun. Motivated by the urgent news of the day and hoping he might break a similarly worthy story, Peter reads the entire diary over the next twenty-four hours, to the consternation of his live-in girl friend, Sigrid Rahn, and learns of significant details in Tauber’s life: In 1941, German Jews Salomon and Esther Tauber are deported to a concentration camp in Riga, Latvia, overseen by the ruthless SS Capt. Eduard Roschmann, nicknamed the “Butcher of Riga” for his sadism. Soon after arriving, on Roschmann’s orders, Esther unwittingly joins several inmates in an unusual bus and all are gassed to death. Although devastated, Salomon survives using his skills as an architect. In October 1944, with the Soviet troops approaching, Roschmann orders several prisoners, including Salomon, to the Riga docks where the captain commandeers a Red Cross ship in which to escape. When an outraged Wehrmacht captain countermands Roschmann’s instructions to remove wounded German troops from the ship, Roschmann shoots and kills the captain. Despite surviving the war and its aftermath, Salomon's hopes of bringing the “Butcher” to justice fade. After reading the diary, Peter wants to write a story on war criminals but after a magazine editor rejects his proposed story, Peter locates Tauber’s sole friend, Marx. Marx reveals that he also is a camp survivor, and that Tauber killed himself after seeing Roschmann alive and learning that the police refused to arrest him because of Odessa. Later, when Karl refuses to reveal any information on Odessa, Peter visits the attorney general’s records office for information on war crimes investigations, but an official informs him that the records on Roschmann are confidential. Noticing an invitation on the official’s desk for a veterans’ reunion scheduled for that night, Peter impulsively decides to attend. The event actually is an SS reunion, and after Peter photographs the guest speaker, he is escorted outside and beaten up. In private, leader General Glücks, who is highly placed in Odessa, learns from associates Werner Deilman and Dr. Ferdinand Schultz that Peter has been seeking information on Roschmann. As Roschmann is deeply involved in the missile tele-guidance development system, Glücks orders Peter to be “taken care of,” then urges the men to speed up work on the tele-guidence project. Hoping to soothe Sigi, who is distressed by his assault, Peter takes her Christmas shopping the next day. While the couple waits for the subway, one of Glücks’s men pushes Peter in front of an approaching train, and Sigi collapses in horror. Peter rolls safely under the platform, however, and is unhurt, but determined to find out who is behind the attack. Taking Tauber’s diary, Peter travels to Vienna to find famed Nazi hunter Simon Wiesenthal. Unable to reach the well-protected Wiesenthal, Peter telephones Karl for help. Unknown to Karl, his partner, Kunik, is an Odessa member and overhearing Karl’s conversation, reports Peter’s whereabouts to Deilman. Through Karl’s assistance, Peter meets Wiesenthal and, giving him Tauber’s diary, details his experiences with Glücks’s men. Wiesenthal explains that Odessa is an organization formed after the war to aid members of the SS to escape war crime prosecution by providing them with new identification and relocation. In nearly two decades, the organization has grown, infiltrating commerce and various fields, including law enforcement. Wiesenthal then provides Peter with information on Roschmann, who escaped Allied capture twice before receiving a new identity from Odessa. Armed with a fairly recent photo of Roschmann provide by Wiesenthal, Peter returns to his hotel where Schultz, using an assumed name, confronts and warns him to give up his inquiry on Roschmann, who Schultz insists is dead. After driving away from the hotel, Peter is followed and later abducted by several men who take him to isolated location where Porath questions him for several hours, suspicious of his meeting with Schultz. When Deilman learns Peter has gone missing, he orders henchman Gustav Mackensen to get information from Sigi. Following Sigi home from work that night, Mackensen chases her down the Elbe tunnel but she flags a passing car, unaware that the driver is Kunik. After establishing that Peter is not involved with Odessa, but intent on finding Roschmann, Porath asks if the reporter would consider going undercover to infiltrate Odessa, and Peter agrees. Meanwhile, in Hamburg, after not hearing from Peter for several days, Sigi warily accepts Kunik’s recommendation to have a policewoman stay with her for protection, unaware that the woman is another Odessa agent. Over the next three weeks, Peter undergoes grueling instruction on SS lore and the details of the life of recently deceased former SS Sgt. Rolf Günther Kolb, whose identity he is to assume. Using the information provided by Porath and his men, Peter, made to look older, makes contact with an Odessa associate in Munich, then is passed on to high-up Franz Bayer. After hours of questioning and authenticating Peter’s credentials, Bayer approves Peter’s request, as Kolb, to receive protection from Odessa. Bayer’s associate escorts Peter to a train station, where he secretly witnesses Peter use the telephone. Peter calls Sigi and reveals his location, which Kunik’s female assistant relays to him. While Peter proceeds to see forger Klaus Wenzer, Deilman realizes from Bayer and Kunik’s reports that “Kolb” is Peter and dispatches Mackensen to Wenzer’s. Upon Peter’s arrival at Wenzer’s, the placid forger tells him that he cannot process the passport until the following Monday. Later, when Mackensen arrives, he forces Wenzer to call Peter and have him return to the printing shop immediately. Suspicious, when Peter arrives he stealthily observes MacKensen waiting alone with a gun, then sneaks into the shop through an upstairs window, which leads to the room of Wenzer’s elderly, infirm mother. Mistaking Peter in his dark clothes for a priest, Frau Wenzer pleads with him to protect her son and reveals that he has a binder of information to save himself from the malevolent forces of Odessa. Peter surprises Mackensen, and after a furious fight and chase to the roof, Mackensen falls to his death through the skylight. Using information provided by Frau Wenzer, Peter finds her son’s binder, which has the identifications of all the SS men for whom he has made false identification documents. Discovering that Roschmann is using the alias "Hans Josef Keifel" and is the head of a large German electronics factory, Peter takes Mackensen’s gun and the binder, which he places in a train station locker, then telephones Sigi. Peter then takes the page with Roschmann’s information to Porath as proof of his discovery and tells him that he will receive the entire binder in exchange for allowing Peter to confront Roschmann alone. Traveling to Heidelberg, Peter waits for Sigi, who has evaded Kunik’s associate to meet him secretly. After confiding all the details to Sigi, Peter gives her the key to the train locker and instructs her to hand deliver the binder to Wiesenthal if he has not returned by the next night. Having learned of a Keifel Electronics gathering the next morning, Peter watches from a distance, and spotting Roschmann, follows him to his vast, isolated villa. Sneaking inside through a cellar door, Peter confronts Roschmann in a large study. After initially denying his real identity, Roschmann admits his past, and then when Peter briefly mentions the diary, delivers a tirade about the greatness of the Nazi past. When Peter shows him a photograph of a Wehrmacht captain and demands to know if Roschmann recalls him, Roschmann blithely admits that the man was an officer he shot for striking him. Peter then tells Roschmann the man was his father, and the older man realizes with horror that family vengeance has been Peter’s motivation to find him, not particular sympathy for Tauber and the murdered Jews. Terrified, Roschmann lunges for a pistol in his desk, forcing Peter to shoot and kill him. Later, Peter is released from police custody without explanation and a mysterious fire, watched by Porath and his men, burns down the Keifel Electronics factory. In spring, Marx visits Jerusalem to say Kaddish for his friend Salomon Tauber.