May 1945. In the aftermath of the Second Word War, the first British War Crimes Investigation Team is assembled to hunt down the senior Nazi officials responsible for the greatest atrocities the world has ever seen. One of the lead investigators is Lieutenant Hanns Alexander, a German Jew serving in the British Army. Rudolf Höss is his most elusive target. As Kommandant of Auschwitz, Hoss not only oversaw the murder of more than one million men, women, and children; he was the man who perfected Hitler's program of mass extermination. This is the story of two German men whose lives diverged, and intersected, in an astonishing way.