Maskerade

The show must go on, as murder, music and mayhem run riot on the night...
The Opera House, Ankh-Morpork...a huge, rambling building, where innocent young sopranos are lured to their destiny by a strangely familiar evil mastermind in a hideously-deformed evening dress...
At least, he hopes so. But Granny Weatherwax, Discworld's most famous witch, is in the audience. And she doesn't hold with that sort of thing.