'Someone knows about them, though.'

'Yes.'

'What shall we do?'

The answer was inevitable. They'd chased a man into the pork futures warehouse, and nearly died. Then they'd ended up in the middle of a small war, and nearly died. Now they were in a mysterious tunnel where there were fresh footprints. If Corporal Carrot-or Sergeant Colon said, 'And what did you do then?', neither of them could face up to the thought of saying 'We came back.'

'The footprints go this way,' said Cuddy, 'and then they return. But the ones coming back aren't so deep as the ones going. You can see they're later ones because they're over the top of the other ones. So he was heavier going than he was coming back, yes?'

'Blight,' said Detritus.

'So that means . . .?'

'He lose weight?'

'He was carrying something, and he left it . . . up ahead somewhere.'

They stared at the darkness.

'So we go and find what it was?' said Detritus.

'I think so. How do you feel?'

'Feel OK.'

Different species though they were, their minds had focused on a single image, involving a muzzle flash and a lead slug singing through the subterranean night.

'He came back,' said Cuddy.

'Yes,' said Detritus.

They looked at the darkness again.

'It has not been a nice day,' said Cuddy.

'That the truth.'

'I'd just like to know something, in case . . . I mean . . . look, what happened in the pork store? You did all that maths! All that counting!'

'I . . . dunno. I saw it all.'

'All what?'

'Just all of it. Everything. All the numbers in the world. I could count them all.'

'What did they equal?'

'Dunno. What does equal mean?'

They trudged on, to see what the future held.

The trail led eventually into a narrower tunnel, barely wide enough for the troll to stand upright. Finally they could go no further. A stone had dropped out of the roof and rubble and mud had percolated through, blocking the tunnel. But that didn't matter because they'd found what they were looking for, even though they hadn't been looking for it.

'Oh dear,' said Detritus.

'Very definitely,' said Cuddy. He looked around vaguely.

'You know,' he said, 'I reckon these tunnels are usually full of water. They're well below the normal river level.'