`And the central rock, no one can jump that, right?' said Vimes.

`Yes.'

`I still think the dwarfs have it all their own way.'

`We shall see. The important thing-'

Vimes stopped when he saw Nobby and Colon. `Okay, lads, I'll talk to the prisoner now,' he said. `How is he?'

Fred indicated the hunched figure on the narrow bunk in the corner cell.

`Captain Carrot tried talking to him for nearly half an hour, and you know he's got a way with people,' he said. `Didn't get as much as a sentence out of him. I read him his rights but don't ask me if he understood 'em. He didn't want his tea and biscuit, at any rate. That's Rights 5 and 5b,' he added, looking Bashfullsson up and down. `He gets Right 5c only if we've got Teatime Assortment:

`Can he walk?' said Vimes.

`He sort of shuffles, sir.'

`Fetch him out, then,' said Vimes, and seeing Fred's enquiring look at Bashfullsson he went on: `This gentleman is here to make sure we don't use the rubber truncheon, sergeant:

`Didn't know we had one, Mister Vimes,' said Fred.

`We haven't,' said Vimes. `No point in hitting 'em with something that bounces, eh?' he added, looking at Bashfullsson, who smiled, once again, his strange little smile.

One candle burned on the table. For some reason Fred had seen fit to put another on a stool near the one occupied cell.

`Isn't it a bit dark in here, Fred?' said Vimes, as he pushed aside the debris of mugs and old newspapers that covered most of the table.

`Yessir. The dwarfs came and nicked some of our candles to put round their heathe- that nasty sign,' said Fred, with a nervous look at Bashfullsson. `Sorry, sir.'

`I don't know why we can't just burn it,' grumbled Vimes, setting out the Thud board.

`That would be dangerous, now that the Summoning Dark is in the world,' said Bashfullsson.

`You believe in that stuff?' said Vimes.

`Believe? No, said the grag. `I just know it exists. The troll pieces go all round the central stone, sir,' he added helpfully.

Populating the board with its little warriors took some time, but so did the arrival of Helmclever. With Fred Colon steering him carefully by a shoulder he walked like someone in a dream, his eyes turned up so that they mostly showed the whites. His iron boots scraped on the flagstones.

Fred pushed him gently into a chair and put the second candle beside him. Like magic, the dwarf's eyes focused on the little stone armies to the exclusion of everything else in the jail.

`We're playing a game, Mr Helmclever,' said Vimes quietly. `And you can choose your side.'

Helmclever reached out with a trembling hand and touched a piece. A troll. A dwarf had chosen to play as the trolls. Vimes gave the hovering Bashfullsson a questioning glance, and got another smile in return.

Okay, you got as many of the little sods as possible in a defensive huddle, right? Vimes's hand hesitated, and shifted a dwarf across the board. The click as he placed it was echoed by the one made by the movement of Helmclever's next troll. The dwarf looked sleepy, but his hand had moved with snake speed.

`Who killed the four mining dwarfs, Helmclever?' said Vimes softly. `Who killed the boys from the city?'

Dull eyes looked at him, and then, meaningfully, at the board. Vimes moved a dwarf at random.

`The dark soldiers,' Helmclever whispered, as a little troll clicked smartly into place.

`Who ordered it?' Again the look, again a dwarf placed at random followed by a troll that was moved so fast the two pieces seemed to hit the board together.

`Grag Hamcrusher ordered it:

`Why?' Click/click.

`They had heard it speaking.'

`What was it that spoke? Was it a cube?' Click/click.

`Yes. It was dug up. It said it spoke with the voice of B'hrian Bloodaxe.'

Vimes heard a gasp from Bashfullsson, and caught Fred Colon's eye. He jerked his head towards the cell-block door, and mouthed a couple of words.

`Wasn't he a famous dwarf king?' said Vimes. Click/click.

`Yes. He commanded the dwarfs at Koom Valley,' said Helmclever.

`And what did this voice say?' said Vimes. Click/click. And a third click from behind Vimes as Fred Colon locked the door and stood in front of it, looking impassive.

`I do not know. Ardent said it was about the battle. He said it was lies.'

`Who killed Grag Hamcrusher?' Click/click.

`I do not know. Ardent called me to the meeting and said there was terrible fighting among the grags. Ardent said one of them killed him in the dark, with a mining hammer, but none knew who. They were all struggling together:

All dressed alike, Vimes thought. Just shapes, if you can't see their wrists ...

`Why did they want to kill him?' Click/click.

`They had to stop him destroying the words! He was screaming and hitting the cube with the hammer!'

`There are ... sensitive areas on a cube and it is possible that if they are touched in the wrong order all the sound will vanish,' whispered Bashfullsson.

`I should think the hammer would do the trick whatever it hit!' said Vimes, turning his head.

`No, commander. Devices are immensely tough. `They must be!'

Vimes turned back to Helmclever. `It's wrong to destroy lies but it's okay to kill the miners?' he said. Click.

He heard the hiss of Bashfullsson's intake of breath. Well, yes, perhaps that could have been better put. There was no answering move. Helmclever hung his head.

`It was wrong to kill the miners,' he whispered. `And why not destroy lies? But it is wrong to think these thoughts, so I ... I said nothing. The old grags were angry and upset and confused, so Ardent took charge. He said one dwarf killing another underground, everyone knew that was no business of humans. He said he could make it all right. He said everyone must listen to him. He told the dark guards to take the body to the new outer chamber. And ... he told me to fetch my club. ..'

Vimes glanced at Bashfullsson and mouthed the word `club?' He got an emphatic nod in return.

Helmclever sat hunched in silence, and then raised one hand slowly and moved a troll. Click.

Click/click. Click/click. Click/click. Vimes tried to spare a few brain cells for the game while his mind raced and laboured to piece together the random information spilling out of Helmclever.

So ... it all starts when they come here looking for this magic cube, which can speak ...

`Why did they come to the city? How did they know the cube was

here?' Click/click.

`When I went to begin my training I took a copy of the Codex. Ardent confiscated it, but then they called me to a meeting and said it was very important and they would honour me by letting me go with them to the city. Ardent told me it was a great opportunity. Grag Hamcrusher had a mission, he said.'

`They hadn't even known about the painting?'

`They lived under a mountain. They believe that humans are not real. But Ardent is smart. He said there were always rumours that something had come out of Koom Valley.'

I bet he is smart, Vimes thought. So they come here, do a little light pastoral work and rabble-rousing, and search for the cube in a very dwarfish way. They find it. But the poor bastards who were doing the digging hear what it's got to say. Well, everyone knows dwarfs gossip, so the dark guards make sure these four don't have a chance to.

Click/click. Click/click.

Then friend Hamcrusher doesn't like what he hears, either. He wants to destroy this thing. In the struggle in the dark one of the other grags does the world a favour and fetches him a crack on the noggin. But, whoops, big mistake, because the mob is going to miss him and his jolly urging to wholesale troll slaughter. You know how dwarfs gossip, and you can't kill 'em all. So while it's still just us together in the dark, we need a plan! Forward, Mr Ardent, who says `I know! We'll take the corpse out to a tunnel that a troll just might have got into, and bash its head in with a club. 'A troll did it. What right-thinking dwarf could possibly believe anything else?