Edinburgh's most unlikely detective duo--"Nine-Nails" McGray and Inspector Ian Frey-- must try to solve a murder mystery on the Scottish stage, as a new production of Macbeth is attracting the machinations of a serial killer . . . Edinburgh, 1889. The Scottish Play is coming home. But before the darlings of London theater--Henry Irving and Ellen Terry--take their acclaimed Macbeth to the Edinburgh stage, terror treads the boards: A grisly...