Ghost riders: Operation Cowboy, the World War Two mission to save the world's finest horses

April 1945. As Allied bombs rain down on Europe, a 400-year-old institution looks set to be wiped off the face of the Earth.

The famous white Lipizzaner stallions of the Spanish Riding School in Vienna, unique and precious animals representing centuries of careful breeding, are scattered across rural Austria and Czechoslovakia in areas soon to be swallowed up by Soviet forces - there, doubtless, to become rations for the Red Army.

Their only hope lies with the Americans: what if a small, highly mobile US task force could be sent deep behind German lines, through fanatical SS troops, to rescue the horses before the Soviets arrive.