In 1939, a visionary aircraft designer called Barnes Wallis had an idea. He would design a very special bomb that would bounce across water and destroy German dams. The raid in 1943 was a success and a 1950s feature film carried the the Dambusters story into British legend. The science behind the bouncing bomb is highly complex, and many of Barnes Wallis's vital working calculations have been lost. Cambridge engineer Dr Hugh Hunt sets out in an to attempt to solve this scientific puzzle. Starting from scratch, he rediscovers the brilliance of Wallis's achievement when he tries to hit a dam with a bouncing bomb. It is the first time this has been attempted since the war. Hugh is assisted by dam engineers, explosives experts, mechanics and pilots who specialise in low altitude flying. A vintage Second World War aircraft is modified to carry a bomb the size of an oil drum.