Vimes turned back to head into the building, and noticed a small, neat figure standing patiently by the door. It had the look of someone who was quite happy to wait. He sighed. I bargain without an axe in my hand, eh?

`Breakfast, Mr Bashfullsson?' he said.

`This is all rather fun,' said Sybil an hour later, as the coaches headed out of the city. `Do you remember when we last went on holiday, Sam?'

`That wasn't really a holiday, dear,' said Vimes. Above them,

Young Sam swung back and forth in a little hammock, cooing. `Well, it was very interesting, all the same,' said Sybil. `Yes, dear. Werewolves tried to eat me.'

Vimes sat back. The coach was comfortably upholstered and well sprung. At the moment, while it threaded through the traffic, the magical loss of weight was hardly noticeable. Would it mean anything? How fast could a bunch of old dwarfs travel? If they really had taken a big wagon, the coaches would catch them tomorrow, when the mountains were still a distant prospect. In the meantime, at least he could get some rest.

He pulled out a battered volume entitled Walking in the Koom Valley, by Eric Wheelbrace, a man who apparently had walked on just about everything bigger than a sheep track in the Near Ramtops. [1] It had a sketch map, the only actual map of the valley Vimes had seen. Eric wasn't a bad sketch artist.

Koom Valley was ... well, Koom Valley was basically a drain,

[1] And even then had been belabouring mountain goats on apparently sheer cliff faces and, while pebbles slid and bounced around him, was clearly accusing them of obstructing his Right to Roam. Eric believed very firmly that The Land Belonged To The People, and also that he was more The People than anyone else was. Eric went everywhere with a map, encased in waterproof material, on a string around his neck. Such people are not to be trifled with.

that's what it was: nearly thirty miles of soft limestone rock edged by mountains of harder rock, so what you had would have been a canyon if it wasn't so wide. One end was almost on the snowline, the other merged into the plains.

It was said that even clouds kept away from the desolation that was Koom Valley. Maybe they did, but that didn't matter. The valley got the water anyway, from meltwater and the hundreds of waterfalls that poured over its walls from the mountains that cupped it. One of those falls, the Tears of the King, was half a mile high.

The Koom River didn't just rise in this valley. It leapt and danced in this valley. By the time it was halfway down, it was a crisscrossing of thundering waters, forever merging and parting. They carried and hurled great rocks, and played with whole fallen trees from the dripping forests that colonized the scree built up against the walls. They gurgled into holes and rose again, miles away, as fountains. They had no mappable course - a good storm higher up the mountains could bring house-sized rocks and half a stricken woodland down in the flood, blocking the sinkholes and piling up dams. Some of these could survive for years, becoming little islands in the leaping waters, growing little forests and little meadows and colonies of big birds. Then some key rock would be shifted by a random river, and within an hour it would all be gone.

Nothing that couldn't fly lived in the valley, at least for long. The dwarfs had tried to tame it, back before the first battle. It hadn't worked. Hundreds of dwarfs and trolls had been swept up in the famous flood, and many had never been found again. Koom Valley had taken them all into its sinkholes and chambers and caverns, and had kept them.

There were places in the valley where a man could drop a coloured cork into a swirling sinkhole and then wait for more than twenty minutes before it bobbed up on a fountain less than a dozen yards away.

There was hardly any sound now. Perhaps sound was unable to keep up.

`Sir?' said Willikins quietly.

`Yes?' said Vimes, his eyes streaming.

`It took us less than a minute to go that last mile. I timed us between milestones, sir.'

`Sixty miles an hour? Don't be daft, man! A coach can't go that fast!'

`Just as you say, sir.'

A milestone flashed past. Out of the corner of his ear, Willikins heard Vimes counting under his breath until, before very long, another stone fell away behind them.

`Wizards, eh?' said Vimes weakly, staring ahead again.

`Indeed, sir,' said Willikins. `May I suggest that once we are

through Quirm we head straight across the grass country?'

`The roads up there are pretty bad, you know,' said Vimes.

`So I believe, sir. However, that will not, in fact, matter,' said the

butler, not taking his eyes off the unrolling road ahead.

`Why not? If we try to go at speed over those rough-'

`I was referring obliquely, sir, to the fact that we are not precisely

touching the ground any more.'

Vimes, clinging with care to the rail, looked over the side. The wheels were turning idly. The road, just below them, was a blur. Ahead of them, the spirit of the horse galloped serenely onwards.

`There's plenty of coaching inns around Quirm,' he said. `We could, er, stop for lunch?'

`Late breakfast, sir! Mail coach ahead, sir! Hold tight!'

A tiny square block on the road ahead was getting bigger quite fast. Willikins twitched the reins, Vimes had a momentary vision of rearing horses, and the mail coach was a dwindling dot, soon hidden by the smoke of flaming brassicas.

'Dem milestones is goin' past real fast now,' Detritus observed, in a conversational tone of voice. Behind him, Brick lay flat on the roof

of the coach with his eyes tight shut, having never before been in a world where the sky went all the way to the ground; there were brass rails around the top of the coach, and he was leaving fingerprints in them.

`Could we try braking?' said Vimes. `Look out! Haycart!'

`That only stops the wheels spinning, sir!' yelled Willikins, as the cart went by with a whoom and fell back into the distance.

`Try pulling on the reins a little!'

`At this speed, sir?'

Vimes slid back the hatch behind him. Sybil had Young Sam on her knee, and was pulling a woolly jumper over his head.

`Is everything all right, dear?' he ventured.

She looked up and smiled. `Lovely smooth ride, Sam. Aren't we going rather fast, though?'

`Er, could you please sit with your back to the horses?' said Sam. `And hold on tight to Young Sam? It might be a bit ... bumpy.'

He watched her shift seats. Then he shut the hatch and yelled to Willikins: `Now!'

Nothing seemed to happen. In Vimes's mind, the milestones were already going zip ... zip as they flashed past.

Then the flying world slowed, while in the fields on either side hundreds of burning cabbages leapt towards the sky, trailing oily smoke. The horse of light and air disappeared and the real horses dropped gently towards the road, going from floating statues to beasts in full gallop without a stumble.

He heard a brief scream as the rear coach tore past and swerved into a field full of cauliflowers where, eventually, it squelched to a flatulent halt. And then there was stillness, except for the occasional thud of a falling cabbage. Detritus was comforting Brick, who'd not picked a good day to go cold turkey; it was turning out to be frozen roc.

A skylark, safely above cabbage range, sang in the blue sky. Below, except for the whimpering of Brick, all was silent.

Absent-mindedly, Vimes pulled a half-cooked leaf off his helmet and flicked it away.

`Well, that was fun,' he said, his voice a little distant. He got down carefully and opened the coach door. `Everyone all right in here?' he said.