The story begins in Nazi Germany, the Third Reich in April 1964, in the week leading up to Adolf Hitler's 75th birthday. The plot follows detective Xavier March, an investigator working for the Kripo (Kriminalpolizei), as he investigates the suspicious death of a high-ranking Nazi (Josef Bühler) in the Havel, on the outskirts of Berlin. As March uncovers more details he realises that he is caught up in a political scandal involving senior Nazi party officials, who are apparently being systematically murdered under staged circumstances.
March meets with Charlie Maguire, a female American journalist who works for the New York Times, who is also determined to investigate the case. They both travel to Zürich to investigate the private Swiss bank account of one of the murdered officials. Ultimately, the two uncover the horrific truth behind the staged murders. The Gestapo is eliminating the remaining officials who planned the Holocaust at the Wannsee Conference of 1942 to safeguard an upcoming meeting of Hitler and President Joseph P. Kennedy by ensuring that details of the secret Holocaust are not revealed. Maguire heads for neutral Switzerland with the evidence, hoping to publish it in the New York Times, but March is apprehended by the Gestapo.
In the cellars of Gestapo headquarters, March is tortured but does not reveal the location of Maguire. The authorities stage a rescue, intending to track March as he meets up with Maguire at their arranged meeting place in Waldshut-Tiengen on the Swiss / German border. March realises what is happening and heads for Auschwitz, leading the authorities in the wrong direction.
The Gestapo catches up with March at the unmarked site of Auschwitz's completely dismantled extermination camp. Believing that Maguire has crossed the border into Switzerland (whether she really does or not is unspecified), he searches for some sign that the death camp was real. As the Gestapo agents converge upon him, March uncovers bricks in the undergrowth.