Deep in the icy waters off Norway, there lies one of the last great secrets of the Second World War. In February 1945, the German submarine U-864 disappeared without trace during the course of a clandestine journey to Japan. The passengers included eighteen of the Reich’s leading aeronautical scientists and two of Japan’s most renowned aerodynamics experts. The craft also contained stacks of blueprints for the Me 262 fighter jet, as well as newly designed Messerschmitt jet engine parts and missile guidance systems. Had this deadly cargo arrived at its destination, revolutionary Nazi jet technology could have affected the course of the Second World War, possibly tipping the balance in favour of the Japanese Air Force in its struggle against the US Navy. Sixty years later, following a chance discovery by local fishermen, we follow a Norvegian salvage team as its intrepid members prepare to recover U-864.