'Let me think now,' said Vimes. 'It could be something to do with a wrongful arrest. It could be something to do with some of the more restless dwarfs just needing any excuse to have a go at the trolls. What do you think, Quirke?'
'I don't think, Vimes.'
'Good man. You're just the type the city needs.'
Vimes stood up.
'I'll be going, then,' he said. 'I'll see you all tomorrow. If there is one.'
The door slammed behind him.
This hall was huge. It was the size of a city square, with pillars every few yards to support the roof. Tunnels radiated off it in every direction, and at various heights in the walls. Water trickled out of many of them, from small springs and underground streams.
That was the problem. The film of running water over the stone floor of the hall had wiped away traces of the footprints.
A very large tunnel, almost blocked with debris and silt, led off in what Cuddy was pretty sure was the direction of the estuary.
It was almost pleasant. There was no smell, other than a damp, under-a-stone mustiness. And it was cool.
'I've seen big dwarf halls in the mountains,' said Cuddy, 'but I've got to admit this is something else.' His voice echoed back and forth in the chamber.
'Oh, yes,' said Detritus, 'it's got to be something else, because it's not a dwarf hall in the mountains.'
'Can you see any way up?'
'No.'
'We could have passed a dozen ways to the surface and not known it.'
'Yes,' said the troll. 'It's a knotty problem.'
'Detritus?'
'Yes?'
'Did you know you're getting smarter again, down here in the cool?'
'Really?'
'Can you use it to think of a way out?'
'Digging?' the troll suggested.
There were fallen blocks here and there in the tunnels. Not many; the place had been well built . . .
'Nah. Haven't got a shovel,' said Cuddy.
Detritus nodded.
'Give me your breastplate,' he said.
He leaned it up against the wall. His fist pounded into it a few times. He handed it back. It was, more or less, shovel shaped.
'It's a long way up,' Cuddy said doubtfully.
'But we know the way,' said Detritus. 'It's either that, or stay down here eating rat for rest of your life.'
Cuddy hesitated. The idea had a certain appeal. . .