The development of a unique weapon that would detonate dams - a bomb that could skip across water, cling to its target and explode at a specific depth.

In 1941, the world was at war and the Allies were desperate to slow the tide of Nazi domination. The Germans needed 100 gallons of water to make one ton of steel. Barnes Wallis, a British aircraft designer, set out to develop a unique weapon that would detonate dams - a bomb that could skip across water, cling to its target and explode at a specific depth to deliver its coup de grâce . This program investigates the urgent rush to create, test and deploy the new bomb, and the efforts to train an elite squadron of pilots for the unusually dangerous low-level night flights to drop it far inside enemy lines. Using archival footage, modern tests of the original principles and equipment, and interviews with experts, participants in the raids and their surviving relatives, the program provides insight into the ingenuity of the man who built the bomb under incredible pressure, as well as the dedication and bravery of the airmen from Britain, Canada, America, Australia and New Zealand who risked (and lost) their lives in one of the most daring missions of WWII.