In the summer of 1944, British soldier Denis Avey was being held in a POW labor camp near Auschwitz III, and having heard rumors of the brutality meted out to the prisoners there, he was determined to witness what he could. Swapping places with a Jewish inmate, Avey smuggled himself into the extermination camp, spending two nights there and experiencing the cruelty of a place where slave workers had been sentenced to death through labor. After decades of silence, Denis Avey tells the gripping, often moving story of what he saw, including the infamous Death March, in which thousands of prisoners were murdered by the Nazis as the Soviet Army advanced.