Wilfred Thesiger observes the monstrous rampart of brick-red dunes ahead of him in despair. He cannot turn back, yet to go forward will risk avalanches of sand and death from dehydration, and if the Arabs find out a Christian is in the uncharted territory of the Empty Quarter then all will certainly be lost. But despite the danger, Thesiger is determined to cross the Sands - and answer the desert's final challange.