It's 1903. Harry Houdini, the great escape artist, seeks the help of Sir Arthur Conan Doyle, creator of Sherlock Holmes, to discredit Maximillian Cairo, an infamous occultist and the most debauched man in London. But the two men get more than they bargained for when they interrupt a magic ritual.That night, they set something loose - something no one can face and stay sane. Something that runs amok, spreading death and madness throughout an unsuspecting Edwardian London.Both men are tortured by self-doubt for the first time in their lives. Have their logical minds been tainted by this brush with frenzy?Their sole hope to understand what is happening to them lies with the only witness to the first murder. But the man refuses to reveal what he's seen, even to save his life.All Houdini's talents and all Conan Doyle's powers of deduction combined may not be enough to save them from what they have unleashed on the world.