Gates exposes Nazi secrets as he searches for the lost fortune of war criminal Adolf Hitler's billions in gold, art and relics stolen on his orders by the Nazis.
They also built networks of hidden tunnels and bunkers.
Today, archaeologists use modern technology to recover treasure and excavate the underground legacy of the Third Reich.
On his journey, Gates joins them, first finding answers in Germany, identifying gold in a Nazi train hidden inside a mountain in Poland.
Then, in Austria, he explores a subterranean facility to a top secret lab to build a war machine.