Winter, 1943. Bernie Gunther has left the Criminal Police and is working for the German War Crimes Bureau based in Berlin. Reports have been circulating of a mass grave hidden in a wood near Smolensk. The grave's whereabouts are uncertain until, deep in the Katyn Forest, a wolf digs up some human remains. Rumour has it that the grave is full of Polish officers murdered by the Russians - a war crime that is perfect propaganda for Germany. But it needs a detective of subtle skill to investigate this horrific discovery. Cue Bernie Gunther.