The magic of the Opera House - where everyone is wound up tighter than a spring, and it's no wonder someone occasionally snaps. And when they snap, they SNAP. With extra exclamation points.

  Detritus sniffed suspiciously, immediately clearing his sinuses. 'What's in it?' he said.
  'Apples,' said Nanny Ogg promply. 'Well...mainly apples.'
  Under her hand, a couple of spilt drops finished eating their way through the metal of the tray and dropped on to the carpet, where they smoked.

Agnes Nitt is fed-up with Lancre; small-minded people living inward-facing little lives on a tiny little bowl of reasonably flat land in the midst of the towering Ramtops. (Of course, most of the Ramtops is technically flat - vertical yes, but flat). Agnes wants a bit more excitement. Ankh-Morpork is bound to have plenty of same, plus a chance to exercise her major talent. She may not be thin, pale or very interesting - in fact, Agnes is large in the geographical sense of the word - but she has an amazing voice. She can sing anything. She can sing duets... with herself! She can harmonise with herself... in fifths! It's absolutely amazing. Why should she spend her life as a barmaid giving renditions of The Hedgehog Song to drunken revellers?

[Incidentally, I was thinking that if we ask Terry nicely, maybe he would post all 979 verses of 'The Hedgehog can never be buggered at all' on his website. And maybe, all 704 versions of 'The Wizard's Staff has a Knob on the End'. Nher nher nher. Dammit. He's turning me into Nobby. Or at least, Truckle the Uncivil. 'Whut?' said Mad Hamish...]

She finds out, however, that fame and fortune are not what they're cracked up to be. The Opera House has a Ghost. Said Ghost has been around for years, but now he's murdering people, and leaving notes with written maniacal laughter. People are starting to demand danger pay, and Dead-Bodies-in-the-Flies bonuses. The Show Must Go On, after all.

* Bergholt Stuttley ('Bloody Stupid') Johnson was Ankh-Morpork's most famous, or rather most notorious, inventor. He was renowned for never letting his number-blindness, his lack of any skill whatsoever, or his complete failure to grasp the essence of a problem, stand in the way of his cheerful progress as the first Counter-Renaissance man. Shortly after building the famous Collapsed Tower of Quirm he turned his attention to the world of music, particularly large organs and mechanical orchestras. Examples of his handiwork still occasionally come to light in sales, auctions and, quite frequently, wreckage.