The story of the "Khyber Pass" tells of the rise and fall of empires, beginning with the great Persian kings Cyrus and Darius, then legendary conquerors Alexander the Great and much later, the White Huns and Genghis Khan. Docherty"s own travels in this true frontier, still largely lawless today, and the continuing presence of US and British troops in Afghanistan bring this story into the twenty-first century.