'She's dead!'
'Carrot! Listen. Can you find the way out in this stuff? No! So come with me!'
'I . . . can't leave her here. I—'
'Corporal Carrot! Follow me!'
Vimes half ran, half waded through the rising water towards the tunnel that had swallowed Cruces. It was up a slope; he could feel the water dropping as he ran.
Never give the quarry time to rest. He'd learned that on his first day in the Watch. If you had to chase, then stay with it. Give the pursued time to stop and think and you'd go round a corner to find a sock full of sand coming the other way.
The walls and ceiling were closing in.
There were other tunnels here. Carrot had been right. Hundreds of people must have worked for years to build this. What Ankh-Morpork was built on was Ankh-Morpork.
Vimes stopped.
There was no sound of splashing, and tunnel mouths all around.
Then there was a flash of light, up a side tunnel.
Vimes scrambled towards it, and saw a pair of legs in a shaft of light from an open trapdoor.
He launched himself at them, and caught a boot just as it was disappearing into the room above. It kicked at him, and he heard Cruces hit the floor.
Vimes grabbed the edge of the hatchway and struggled through it.
This wasn't a tunnel. It looked like a cellar. He slipped on mud and hit a wall clammy with slime. What was Ankh-Morpork built on? Right. . .
Cruces was only a few yards away, scrambling and slipping up a flight of steps. There had been a door at the top but it had long ago rotted.
There were more steps, and more rooms. Fire and flood, flood and rebuilding. Rooms had become cellars, cellars had become foundations. It wasn't an elegant pursuit; both men slithered and fell, clambered up again, fought their way through hanging curtains of slime. Cruces had left candles here and there. They gave just enough light to make Vimes wish they didn't.
And then there was dry stone underfoot and this wasn't a door, but a hole knocked through a wall. And there were barrels, and sticks of furniture, ancient stuff that had been locked up and forgotten.
Cruces was lying a few feet away, fighting for breath and hammering another rack of pipes into the gonne. Vimes managed to pull himself up on to his hands and knees, and gulped air. There was a candle wedged into the wall nearby.
'Got. . . you,' he panted.
Cruces tried to get to his feet, still clutching the gonne.
'You're . . . too old . . . to run . . .' Vimes managed.
Cruces made it up upright, and lurched away. Vimes thought about it. 'I'm too old to run,' he added, and leapt.
The two men rolled in the dust, the gonne between them. It struck Vimes much later that the last thing any man of sense would do was fight an Assassin. They had concealed weapons everywhere. But Cruces wasn't going to let go of the gonne. He held it grimly in both hands, trying to hit Vimes with the barrel or the butt.
's Detritus the troll, sir.'
'Why is he sitting like that?'
'He's thinking, sir.'
'He hasn't moved for some time.'
'He thinks slow, sir.'
Detritus stood up. There was something about the way he did it, some hint of a mighty continent beginning a tectonic movement that would end in the fearsome creation of some unscalable mountain range, which made people stop and look. Not one of the watchers was familiar with the experience of watching mountain building, but now they had some vague idea of what it was like: it was like Detritus standing up, with Cuddy's twisted axe in his hand.