October 1944, Auschwitz-Birkenau.Saul Auslander is a Hungarian member of the Sonderkommando, the group of Jewish prisoners isolated from the camp and forced to assist the Nazis in the machinery of large-scale extermination.

While working in one of the crematoriums, Saul discovers the corpse of a boy he takes for his son.As the Sonderkommando plans a rebellion, Saul decides to carry out an impossible task: save the child's body from the flames, find a rabbi to recite the mourner's Kaddish and offer the boy a proper burial.