Synopsis

The 1944 sinking of the Norwegian ferry Hydro, laden with "heavy water" for the Nazis' clandestine atomic bomb program, remains one of World War II’s most audacious covert operations. While the mission was officially deemed successful, the presence of the vital shipment aboard the vessel was never definitively confirmed. In this program, NOVA journeys 1,300 feet beneath a secluded Norwegian lake in search of the truth.