The Snowy Mountains Hydro-Electric Scheme is one of the world's greatest engineering achievements. Its development involved blasting 12 tunnels through the mountains, the building of 16 dams to hold the water and feed it through seven power stations, two of them deep in the mountains. Into the technical achievement and political background are interwoven the story of the hardships suffered and the contribution of the thousands who helped to build it - the people, the dramas, the tragedy, the triumphs and the humour.