'Search me,' said the oh god, who'd backed away hurriedly. 'Er ... just then ...  before you turned your face away ... it looked as though  you were wearing very dark eye shadow ... only you weren't ...'

     'Look, it's  very simple,' said Susan, spinning round.  She  could feel her hair restyling  itself, which it  always did when  it  was anxious. 'You know how stuff runs  in families? Blue eyes, buck teeth, that sort of thing? Well, Death runs in my family.'

     'Er ... in everybody's family, doesn't it?' said the oh god.

     'Just shut up, please, don't gabble,' said Susan. ,I didn't mean death, I meant Death with a capital D. I remember things that haven't happened  yet and  I  Can  TALK  THAT  TALK  and  stalk  that stalk  and ...  if  he  gets sidetracked,  then I'll have to do it. And he  does get sidetracked. I don't know what's really happened to the real Hogfather or why Grandfather's doing his job, but I know a  bit about how he thinks and he's got no ... no mental shields like we have. He doesn't know how to forget things or ignore things. He takes everything literally and logically and doesn't understand why  that doesn't always work ...'

     She saw his bemused expression.

     'Look ... how would you make sure everyone in  the world was well fed?' she demanded.

     'Me? Oh,  well, I...'  The oh god  spluttered for a  moment. 'I suppose you'd have to think about the prevalent  political systems,  and the  proper division and cultivation of arable land, and ...'

     'Yes, yes. But he'd just give everyone a good meat' said Susan.

     'Oh, I see.  Very impractical. Hah, it's as silly  as saying  you could clothe the naked by, well, giving them some clothes.'

     'Yes! I mean, no. Of course not!  I mean, obviously you'd give... oh, you know what I mean!'

     'Yes, I suppose so.'

     'But he wouldn't.'

     There was a crash beside them.

     A burning wheel always rolls out  of flaming wreckage. Two men carrying a large sheet of glass always cross  the road in  front of any comedy  actor involved in a crazy car chase. Some narrative conventions are so strong that equivalents happen even on planets where the rocks boil at noon. And  when a fully  laden table collapses,  one  miraculously unbroken plate always rolls across the floor and spins to a halt.

     Susan and the oh god watched it, and then turned their attention to the huge figure now lying  in what  remained of an enormous  centrepiece made of fruit.

     'He just ... came right out of the air,' whispered the oh god.

     'Really?  Don't just  stand there. Give me a hand to help  him up, will you?' said Susan, pulling at a large melon.

     'Er, that's a bunch of grapes behind his ear ...'

     'Well?'

     'I don't like even to think about grapes ...'

     'Oh, come on.'

     Together they managed to get the newcomer on to his feet.

     'Toga, sandals ... he looks  a bit  like you,' said Susan, as the fruit victim swayed heavily.

     'Was I that green colour?'

     'Close.'

     'Is ... is there a privy nearby?' mumbled their  burden, through clammy lips.

     'I believe it's through that arch  over there,' said Susan. 'I've heard it's not very pleasant, though.'

     'That's  not  a  rumour, that's a  forecast,' said the fat figure,  and lurched off. 'And then can  I please have a glass of water and one  charcoal biscuit. . .'

     They watched him go.

     'Friend of yours?' said Susan.

     'God  of Indigestion,  I think. Look ... I ...  er  ... I  think  I  do remember something,' said the oh god- 'Just before I, um, incarnated. But it sounds stupid. .

     'Well?'

     'Teeth,' said the oh god.

     Susan hesitated.

     'You don't mean something attacking you, do you?' she said flatly.

     'No. Just ... a sensation of toothiness. Probably doesn't mean much. As God of Hangovers I see a lot worse, I can tell you.'

     `Just teeth. Lots of teeth. But not horrible  teeth. just lots and lots of little teeth. Almost ... sad?'

     'Yes! How did you know?'

     'Oh, I ... maybe I remember you telling me before you told me. I don't know. How about a big shiny red globe?'

     The oh  god looked  thoughtful for a  moment and  then said, 'No, can't help you there, I'm afraid. It's just teeth. Rows and rows of teeth.'

     'I  don't  remember rows,'  said  Susan.  'I just felt ...  teeth  were important.'

     'Nah,  it's amazing what you can do with a beak,' said the raven, who'd been investigating the laden table and had succeeded in levering a lid off a jar.

     'What have you got there?' said Susan wearily.

     'Eyeballs,' said  the raven. 'Hah, wizards know how to live all right," eh? They don't want for nothing around here, I can tell you.'

     'They're olives,' said Susan.

     'Tough luck,' said the raven. 'They're mine now.'

     'They're a kind of fruit! Or a vegetable or something!'

     'You sure?'  The raven swivelled one  doubtful  eye on the jar  and the other on her.

     'Yes!'

     The eyes swivelled again.

     'So you're an eyeball expert all of a sudden?'

     'Look they're green, you stupid bird!'

     'They could be very old eyeballs,' said the raven defiantly. 'Sometimes they go like that ...'

     SQUEAK, said the Death of Rats, who was halfway through a cheese.

     '...And  not  so much  of  the  stupid,'  said the  raven.  'Corvids  are exceptionally bright with reasoning      and, in the case of some forest species, tool-using abilities!'

     'Oh, so you are an expert on ravens, are you?' said Susan.

     'Madam, I happen to be a ...'

     SQUEAK, said the Death of Rats again.

     They both turned. It was pointing at its grey teeth.

     'The Tooth Fairy?' said Susan. 'What about her?'

SQUEAK.

     `Rows of teeth,' said the oh god  again. 'Like ... rows,  you  know? What's the Tooth Fairy?'

     'Oh, you  see  her around a  lot  these days,'  said Susan.  'Or  them, rather. Its a sort of franchise operation. You get the ladder, the moneybelt and the pliers and you're set up.'

     'Pliers?'

     'If she  can't make change she has  to take an extra tooth  on account. But, look, the tooth fairies are harmless  enough. I've met  one  or  two of them. They're just working girls. They don't menace anyone.'

SQUEAK.

     'I just hope Grandfather doesn't take it into his head to do  their job as well. Good grief, the thought of it ...'

     'They collect teeth?'

     'Yes. Obviously.'

     'Why?'

     'Why? It's their job.'

     'I meant why, where do they take the teeth after they collect them?'

     'I don't  know! They just ... well, they just  take the teeth and leave the money,' said Susan. 'What sort of question is that - 'Where do they take the teeth?'?'

     'I just wondered, that's all. Probably  all humans  know, I'm  probably very silly for asking, it's probably a wellknown fact.'

     Susan looked thoughtfully at the Death of Rats.

     'Actually ... where do they take the teeth?'

SQUEAK?

     'He says search  him,' said the raven. 'Maybe they sell 'em?' It pecked at another jar. 'How about these, these look nice and wrinkl...'

     'Pickled  walnuts,'  said Susan  absently.  'What  do they  do with the teeth? What  use is there for a lot  of teeth? But ... what harm can a tooth fairy do?'

     'Have we got time to find one and ask her?' said the oh god.

     'Time isn't the problem,' said Susan.

     There are those who believe knowledge is something that is acquired - a precious ore hacked, as it were, from the grey strata of ignorance.