'I'm not sure I understand.'
Cuddy shivered, and stamped his feet to keep warm.
'Let's get out of here.'
They trotted to the door. It was shut fast.
'Can you knock it down?'
'No. If this place wasn't troll proof, it'd be empty. Sorry.'
'Detritus?'
'Yes?'
Are you all right? Only there's steam coming off your head.'
'I do feel . . . er . . .'
Detritus blinked. There was a tinkle of falling ice. Odd things were happening in his skull.
Thoughts that normally ambulated sluggishly around his brain were suddenly springing into vibrant, coruscat-ing life. And there seemed to be more and more of them.
'My goodness,' he said, to no-one in particular.
This was a sufficiently un-troll-like comment that even Cuddy, whose extremities were already going numb, stared at him.
'I do believe,' said Detritus, 'that I am genuinely cogitating. How very interesting!'
'What do you mean?'
More ice cascaded off Detritus as he rubbed his head.
'Of course!' he said, holding up a giant finger. 'Superconductivity!'
'Wha'?'
'You see? Brain of impure silicon. Problem of heat dissipation. Daytime temperature too hot, processing speed slows down, weather gets hotter, brain stops completely, trolls turn to stone until nightfall, ie, colder-temperature,however,lowertemperatureenough,brain operatesfasterand—'
'I think I'm going to freeze to death soon,' said Cuddy.
Detritus looked around.
'There are small glazed apertures up there,' he said.
'Too hi' to rea', e'en if I st' on y'shoulders,' mumbled Cuddy, slumping down further.
'Ah, but my plan involves throwing something through them to attract help,' said Detritus.
'Wha' pla'?'
'I have in fact eventuated twenty-three but this one has a ninety-seven per cent chance of success,' said Detritus, beaming.
'Ha'nt got an'ting t'throw,' said Cuddy.
'I have,' said Detritus, scooping him up. 'Do not worry. I can compute your trajectory with astonishing precision. And then all you will need to do is fetch Captain Vimes or Carrot or someone.'
Cuddy's feeble protests described an arc through the freezing air and vanished along with the window glass.