'Smartest thing on a troll,' said Sergeant Colon.

And then the world exploded.

The Watch had left before Captain Vimes got back to Pseudopolis Yard. He plodded up the stairs to his office, and sat down in the sticky leather chair. He gazed blankly at the wall.

He wanted to leave the Guard. Of course he did.

It wasn't what you could call a way of life. Not life.

Unsocial hours. Never being certain from one day to the next what the Law actually was, in this pragmatic city. No home life, to speak of. Bad food, eaten when you could; he'd even eaten some of Cut-Me-Own-Throat Dibbler's sausages-in-a-bun before now. It always seemed to be raining or baking hot. No friends, except for the rest of the squad, because they were the only people who lived in your world.

Whereas in a few days he would, as Sergeant Colon had said, be on the gravy boat. Nothing to do all day but eat his meals and ride around on a big horse shouting orders at people.

At times like this the image of old Sergeant Kepple floated across his memory. He'd been head of the Watch when Vimes was a recruit. And, soon afterwards, he retired. They'd all clubbed together and bought him a cheap watch, one of those that'd keep going for a few years until the demon inside it evaporated.

Bloody stupid idea, Vimes thought moodily, staring at the wall. Bloke leaves work, hands in his badge and hourglass and bell, and what'd we get him? A watch.

But he'd still come in to work the next day, with his new watch. To show everyone the ropes, he said; to tidy up a few loose ends, haha. See you youngsters don't get into trouble, haha. A month later he was bringing the coal in and sweeping the floor and running errands and helping people write reports. He was still there five years later. He was still there six years later, when one of the Watch got in early and found him lying on the floor . . .

And it emerged that no-one, no-one, knew where he lived, or even if there was a Mrs Kepple. They had a whip-round to bury him, Vimes remembered. There were just guards at the funeral . . .

Come to think of it, there were always just guards at a guard's funeral.

Of course it wasn't like that now. Sergeant Colon had been happily married for years, perhaps because he and his wife arranged their working lives so that they only met occasionally, normally on the doorstep. But she left him decent meals in the oven, and there was clearly something there; they'd got grandchildren, even, so obviously there had been times when they'd been unable to avoid each other. Young Carrot had to fight young women off with a stick. And Corporal Nobbs . . . well, he probably made his own arrangements. He was said to have the body of a twenty-five year old, although no-one knew where he kept it.

mber,' he said, 'let's be careful out there.'

'Yeah,' said Nobby, 'let's be careful to stay in here.'

To understand why dwarfs and trolls don't like each other you have to go back a long way.

They get along like chalk and cheese. Very like chalk and cheese, really. One is organic, the other isn't, and also smells a bit cheesy. Dwarfs make a living by smashing up rocks with valuable minerals in them and the silicon-based lifeform known as trolls are, basically, rocks with valuable minerals in them. In the wild they also spend most of the daylight hours dormant, and that's not a situation a rock containing valuable minerals needs to be in when there are dwarfs around. And dwarfs hate trolls because, after you've just found an interesting seam of valuable minerals, you don't like rocks that suddenly stand up and tear your arm off because you've just stuck a pick-axe in their ear.

It was a state of permanent inter-species vendetta and,

-like all good vendettas, didn't really need a reason any more. It was enough that it had always existed.[5] Dwarfs hated trolls because trolls hated dwarfs, and vice versa.

The Watch lurked in Three Lamps Alley, which was about halfway down Short Street. There was a distant crackle of fireworks. Dwarfs let them off to drive away evil mine spirits. Trolls let them off because they tasted nice.

'Don't see why we can't let 'em fight it out amongst themselves and then arrest the losers,' said Corporal Nobbs. 'That's what we always used to do.'

'The Patrician gets really shirty about ethnic trouble,' said Sergeant Colon moodily. 'He gets really sarcastic about it.'

A thought struck him. He brightened up a little bit.

'Got any ideas, Carrot?' he said.

A second thought struck him. Carrot was a simple lad.

'Corporal Carrot?'

'Sarge?'

'Sort this lot out, will you?'

Carrot peered around the corner at the advancing walls of trolls and dwarfs. They'd already seen each other.

'Right you are, sergeant,' he said. 'Lance-Constables Cuddy and Detritus – don't salute! – you come with me.'