It looked so simple. It would have been simple if Koom Valley had been flat and not littered with rubbish like the ten-pin bowling alley of the gods. In some places they had to backtrack because a rampart of tangled, stinking, gnat-infested timber blocked the way. Or the barrier was a wall of rocks the length of a street. Or a wide, mist-filled, thundering cauldron of white water that elsewhere would have a name like The Devil's Cauldron but here was nameless because this was Koom Valley and for Koom Valley there just weren't enough devils and they didn't have enough cauldrons.

And the flies stung and the sun shone and the rotting wood and damp air and lack of wind created a sticky, swamp-like miasma that seemed to weaken the muscles. No wonder they fought at the other end of the valley, Vimes thought. There was air and wind up there. At least you'd be comfortable.

Sometimes they'd come out into a clear stretch that looked like the scene that Methodia Rascal had painted, but the nearby mountains didn't quite match up, and it was off again into the maze. You had to detour, and then detour around the detour.

At last Vimes sat down on a bleached, crumbling log and put the paper aside.

`We must've missed it,' he said, panting. `Or Rascal didn't get the mountains quite right. Or maybe even a slice of mountain fell off in the last hundred years. It could have happened. We could be twenty feet away from whatever it is we're looking for and still miss it.' He slapped a gnat off his wrist.

`Cheer up, sir, I think we're fairly close,' said Cheery.

`Why? What makes you think that?' said Vimes, wiping his brow.

`Because I think you may be sitting on the painting, sir. It's very dirty, but that looks like rolled-up canvas to me.'

Vimes stood up quickly and inspected the log. One corner of what he'd taken to be yellow-grey bark peeled back to reveal paint on the other side.

`And those timbers over there-' Cheery began, but stopped because Vimes had raised a finger to his lips.

There were indeed some long thin pine saplings lying near by, stripped of all branches. They would have gone unnoticed if it weren't for the presence of the rolled-up painting.

They did just what we did, Vimes thought. It was probably easier, if they had enough dwarfs to hold up the painting; the mountains would be properly coloured, not just pencil lines, and it would be more accurate on the bigger canvas. They could take their time, too. They thought they were well ahead of me. All they were worried about was some bloody mystic symbol.

He drew his sword and beckoned Cheery to follow him.

There's not just dark dwarfs here, then, he thought, creeping around the nearby rocks. They wouldn't have stood out here in daylight. So let's see how many stayed on guard ...

None, as it turned out. It was something of an anticlimax. Beyond the rocks was the spot that X would have marked, if there had been an X.

They must have been really confident, Vimes realized. By the look of it, they'd moved tons of rock and stricken timber, and there were the crowbars to prove it.

Right now would be a really good time for Angua and the others to catch us up, he decided.

In front of them was a hole about six feet wide. A steel bar had been laid across it, bedded into two freshly chiselled grooves, and from the bar a stout rope disappeared into the depths. From far below came the thunder of dark waters.

`Mr Rascal must've been a brave man to stand here,' said Vimes. `I expect it was a plugged hole a hundred years ago,' said Cheery. `I'll tell you what,' said Vimes, kicking a pebble into the dark.

`Pretend I'm a city man who doesn't know a bloody thing about caves, why don't you?'

`It's what you get when a hole gets blocked, sir,' said Cheery patiently. 'Mr Rascal probably just had to climb down on to a plug of debris.'

This is the place.

So ... this is where he found the talking cube, Vimes thought. Ignoring Cheery's protests, because he was the commander around here, he swung down on to the rope and lowered himself a few feet.

There, tucked under the lip of the hole, a stubby piece of iron was rusted into the rock. A few links of equally rusted chain hung from it.

It sang in its chains ...

`There was a note about the thing being in chains,' he said. `Well,

there's some chain here, and what could be the stub of a knife!' `Dwarf steel, sir!' said Cheery reproachfully. `It does last.' `It could last all that time?'

`Oh yes. I expect the sink became a fountain for a while after Rascal's day, and forced the blockage out. That sort of thing happens all the time in Koom Va- Er, what are you doing, sir?'

Vimes was staring down into the darkness. Below, unseen, dark waters churned. So ... the messenger climbed up this hole, he thought. Where to hide the cube safely? There could be trolls up

above? But a fighting dwarf would have a dagger, certainly, and they love chains. Yes ... here would be a good place. And he'd be back soon, anyway ...

`Old men climbed down this?' he said, staring down the rope into the dark.

`Old dwarfs, sir. Yes. We're strong for our size. You're not going down, are you, sir?'

There's a side tunnel down there ...

`There must be a side tunnel down there,' said Vimes. Thunder rumbled, far up in the mountains.

`But the others will be here soon, sir! Aren't you rushing things?'

Don't wait for them.

`No. Tell them to follow me. Look, we've lost time. I can't hang around all day.'

Cheery hesitated and then pulled something out of a pouch on her belt.

`Then at least take these, sir,' she said. He grabbed the little package as it fell. It was surprisingly heavy.

`Waxed matches, sir, they don't get wet. And the wrapping will burn like a torch for at least four minutes. There's a small loaf of dwarf bread, too.'

`Well ... thank you,' said Vimes, to the worried round shadow against the yellow sky. `Look, I'll see if there's any light down there, and if there isn't, I'll come straight back. I'm not that daft.'

He let himself slide down the rope. There was a knot every couple of feet. The air was winter cold after the heat of the valley. Fine spray came up from below.

There was a tunnel, well above the cauldron. He could make himself believe there was light in the distance, too. Well, he wasn't stupid. He needed to

Letgo...

His hands loosened their grip. He didn't even have time to swear before the water closed over him.

Vimes opened his eyes. After a while, moving his arm slowly because of the pain, he found his face and checked that his eyelids were, indeed, open.

Which bits of his body weren't aching? He checked. No, there seemed to be none. His ribs were carrying the melody of pain, but knees, elbows and head were all adding trills and arpeggios. Every time he shifted to ease the agony, it moved somewhere else. His head ached as if someone was hammering on his eyeballs.

He groaned, and coughed up water.

Gritty sand was under him. He could hear the rush of water somewhere near by, but the sand under him was merely damp. And that didn't seem right.

He risked turning over, a process that extracted a considerable amount of groan.

He could remember the icy water. There had been no question of swimming. All he'd been able to do was roll himself into a ball as the water threw and scraped and banged him through the bagatelle board of Koom Valley. He'd gone over an underground waterfall once, he was sure, and had managed to suck a breath before being whisked onward. And then there was depth, and pressure, and his life started to unroll before his eyes, and his last thought had been please, please, can we skip the bit with Mavis Trouncer ...

And now he was here on an invisible beach, totally out of the water? But this place surely didn't have tides!