On a snowy January morning in 1889, a worried servant hacked open a locked door at the remote hunting lodge deep in the Vienna Woods. Inside, he found two bodies sprawled on an ornate bed, blood oozing from their mouths. Crown Prince Rudolf of Austria-Hungary appeared to have shot his seventeen-year-old mistress Baroness Mary Vetsera as she slept, sat with the corpse for hours and, when dawn broke, turned the pistol on himself. A century has transformed this bloody scene into romantic tragedy: star-crossed lovers who preferred death together than to be parted by a cold, unfeeling Viennese Court. But Mayerling is also the story of family secrets: incestuous relationships and mental instability; blackmail, venereal disease, and political treason; and a disillusioned, morphine-addicted Crown Prince and a naïve schoolgirl caught up in a dangerous and deadly waltz inside a decaying empire. What happened in that locked room remains one of history's most evocative mysteries: What led Rudolf and mistress to this desperate act? Was it really a suicide pact? Or did something far more disturbing take place at that remote hunting lodge and result in murder? Drawing interviews with members of the Habsburg family and archival sources in Vienna, Greg King and Penny Wilson reconstruct this historical mystery, laying out evidence and information long ignored that conclusively refutes the romantic myth and the conspiracy stories.