"Nazi Supergun" is a documentary program which examines an attempt by the Nazis to create a gun that could reach London from the shores of France. In the summer of 1944, the Allied forces discovered the Nazis had built a massive complex on the French coast to house the enormous gun (known as the V3). In an attempt to destroy the V3, the Americans tried to fly a plane packed with explosives into the complex; however, the plane exploded before reaching its destination, resulting in the death of its pilot Joe Kennedy Jr. Meanwhile, the British engineer Barnes Wallis invented a huge bomb, known as the "earthquake bomb", which succeeded in destroying the Nazi project. The program covers the development of both the V3 and the Allied force's solutions, and will also focus on Joe Kennedy Jr.'s unfortunate role in the mission. Current day experiments will also be done to determine why Kennedy's plane exploded, and also whether it was possible to create a gun that could bomb London from the French coast.