Just off Florida's coast, Josh Gates braves shark-infested waters in search of an American ship sunk by a Nazi U-boat during WWII. Josh joins Tristan Guttridge who has a bold new strategy to use sharks as spies to uncover the wreck.

Josh meets the restoration team of the Fleet Air Arm Museum searching for parts of Fairey Barracudas, a model of British bombers of which no intact examples exist. He excavates a former airfield in St Andrews, Scotland then finds wreckage near Alta in the far north of Norway, where Barracudas once attacked the Nazi battleship Tirpitz.