From the back cover: "Armed with the uncanny powers to cloak himself in darkness and control the minds of others, Lamont Cranston makes the crime-scourged streets of 1930s New York the battleground in a war against the dark forces he once embraced. The battle will unite Cranston with his extraordinary soul mate, Margo Lane. And it will pit him against the unspeakable Shiwan Khan--a brilliant madman filled with his ancient ancestor's lust for conquest, and appetite for annihilation...."