The submarine was envisaged as the ultimate weapon of destruction, and by the peak of the Cold War it could stay submerged for months and destroy a city with a single warhead. Michael Gambon narrates the story of the engineers and sailors who pioneered the creation of America's USS Nautilus, the world's first nuclear submarine, and their Russian counterparts who worked on the K-3. Includes previously classified material and interviews with the submarines' captains and crew.