Bob Baer and John Cencich return with new experts and new technology to examine Adolf Hitler's possible escape from every angle; the team returns to Berlin, where Lenny DePaul and Sascha Keil discover an unknown fifth exit from Hitler's Fuhrerbunker.

While investigating makeshift runways, the team finds reason to believe Adolf Hitler would have had a stopping point on the way to Spain; Lenny and historian James Holland head to Denmark, where they investigate an airstrip and a bunker system.

A document shows Adolf Hitler and Leon Degrelle may have moved from Denmark to San Sebastian, Spain; the South American team speaks to an eyewitness who claims his father worked for Hitler's right-hand man, Martin Bormann, after the end of the war.

While following leads on a Nazi escape network, the teams in Southern Spain and Northern Argentina both make discoveries of vast tunnel systems in the mountains.

Bob and John’s investigation continues in Spain, Morocco and Argentina. The teams look into Hitler’s possible escape route while uncovering a plan for a Nazi 4th Reich.

Digging deeper into reports about the Fourth Reich, Bob and John send the team to a rumored weapons testing site in Germany, and a mysterious deserted island in Argentina that could have housed nuclear facilities with Nazi ties after the war.

Bob and John have followed hundreds of international declassified files all the way from Berlin to Chile, where they now investigate a secretive German community with reported Nazi ties. Inside the compound they find clues pointing to the potential forming of a Fourth Reich.