The killing joke - Anthony Horowitz

When Guy Fletcher protests at a feeble joke he overhears in his grotty local pub, he finds himself headbutted and struck by an idea in quick succession. Is it possible to trace a joke all the way back to its original source?

So begins his quest: to follow this sorry joke back to its creator. It's a meandering trail across the UK that takes him from a humourless Hungarian dentist in Muswell Hill to a hyperactive troupe of Boy Scouts in St Albans, from a group of giggling grave-diggers in Saffron Walden to a pickpocket in Stoke-on-Trent. (Just how does he get Guy's watch?) And there are some pretty odd things happening along the way. Guy is sure he's being followed by a sinister Englishman, Irishman and Scotsman. He has an unfortunate accident on a banana skin. There's a fly in his soup. An army of nuns swamp his train. And then there's the exploding house in Cambridge.

Just as Guy thinks he's getting close to uncovering the original source of the joke, the trail stops cold. Or rather, the last link in the chain is crushed by a falling grandfather clock. Guy is on the verge of discovering something very unpleasant. Making jokes is no laughing matter...