Good old Dame Fortune. You can depend on her.
The fog closed in, making every light a dim glow and muffling all sounds. It was clear to Sergeant Colon and Corporal Nobbs that no barbarian horde would be including the invasion of Ankh-Morpork in their travel plans for this evening. The watchmen didn't blame them.
They closed the gates. This was not the ominous activity that it might appear, since the keys had been lost long ago and latecomers usually threw gravel at the windows of the houses built on top of the wall until they found a friend to lift the bar. It was assumed that foreign invaders wouldn't know which windows to throw gravel at.
Then the two watchmen trailed through the slush and muck to the Water Gate, by which the river Ankh had the good fortune to enter the city. The water was invisible in the dark, but the occasional ghostly shape of an ice floe drifted past below the parapet.
'Hang on,' said Nobby, as they laid hands on the windlass of the portcullis. 'There's someone down there.'
'In the river?' said Colon.
He listened. There was the creak of an oar, far below.
Sergeant Colon cupped his hands around his mouth and issued the traditional policeman's cry of challenge.
'Oi! You!'
For a moment there was no sound but the wind and the gurgling of the water. Then a voice said: 'Yes?'
'Are you invading the city or what?'
There was another pause. Then:
'What?'
'What what?' said Colon, raising the stakes.
'What were the other options?'
'Don't mess me about... Are you, down there in the boat, invading this city?'
'No.'
'Fair enough,' said Colon, who on a night like this would happily take someone's word for it. 'Get a move on, then, 'cos we're going to drop the gate.'
After a while the splash of the oars resumed and disappeared downriver.
'You reckon that was enough, just askin' 'em?' said Nobby.
'Well, they ought to know,' said Colon.
'Yeah, but--'
'It was a tiny little rowin' boat, Nobby. Of course, if you want to go all the way down to them nice icy steps on the jetty--'
'No, sarge.'
'Then let's get back to the Watch House, all right?'
William turned up his collar as he hurried towards Cripslock the engraver. The usually busy streets were deserted. Only those people with the most pressing business were out of doors. It was turning out to be a very nasty winter indeed, a gazpacho of freezing fog, snow and Ankh-Morpork's ever-present, ever-rolling smog.
His eye was caught by a little pool of light by the Watchmakers' Guild. A small hunched figure was outlined in the glow.
He wandered over.
A hopeless sort of voice said, 'Hot sausages? Inna bun?'
'Mr Dibbler?' said William.