Brand-new evidence reveals the secrets of a Nazi program to build a nuclear bomb, and using cutting-edge science and tech, experts uncover classified files that reveal how closer Hitler came to this terrifying superweapon.

A nuclear submarine spying on Soviet maneuvers goes missing, and its wreckage is mysteriously found on the ocean floor; the US Navy claims it was an accident, but declassified documents reveal startling new information that points to a Cold War coverup.