It was the following morning. I was sitting at the kitchen table staring at my ring finger and the complete absence of a wedding band. Mum walked in wrapped in a dressing gown and with her hair in curlers, fed DH82, let Alan out of the broom cupboard where we had to keep him these days and pushed the delinquent dodo outside with a mop. He made an angry plinking noise, then attacked the boot-scraper.

'What's wrong, sweetheart?'

'It's Landen.'

'Who?'

'My husband. He was reactualised last night but only for about two hours.'

'My poor darling! That must be very awkward.'

'Awkward? Extremely. I climbed naked into bed with Mr and Mrs Parke-Laine.'

My mother went ashen and dropped a saucer.

'Did they recognise you?'

'I don't think so.'

'Thank the GSD for that!' she gasped, greatly relieved. Being embarrassed in public was something she cared to avoid more than anything else, and having a daughter climbing into bed with patrons of the Swindon Toast League was probably the biggest faux pas she could think of.

'Good morning, pet,' said Mycroft, shuffling into the kitchen and sitting down at the breakfast table. He was my extraordinarily brilliant inventor uncle, and apparently had just returned from the 1988 Mad Scientists Conference, or MadCon '88 as it was known.

'Uncle,' I said, probably with less enthusiasm than I should have mustered, 'how good to see you again!'

'And you, my dear,' he said kindly. 'Back for good?'

'I'm not sure,' I replied, thinking about Landen. 'Aunt Polly well?'

'In the very best of health. We've been to MadCon — I was given a lifetime achievement award for something but for the life of me I can't think what, or why.'

It was a typically Mycroft statement. Despite his undoubted brilliance, he never thought he was doing anything particularly clever or useful — he just liked to tinker with ideas. It was his Prose Portal invention which had got me inside books in the first place. He had set up home in the Sherlock Holmes canon to escape Goliath but had remained stuck there until I rescued him about a year ago.

'Did Goliath ever bother you again?' I asked. 'After you came back, I mean?'

'They tried,' he replied softly, 'but they didn't get anything from me.'

'You wouldn't tell them anything?'

'No. It was better than that. I couldn't. You see, I can't remember a single thing about any of the inventions they wanted me to talk about.'

'How is that possible?'

'Well,' replied Mycroft, taking a sip of tea, 'I'm not sure, but logically speaking I must have invented a memory erasure device or something and used it selectively on myself and Polly — what we call the Big Blank. It's the only possible explanation.'

'So you can't remember how the Prose Portal actually works?'

'The what?'

'The Prose Portal. A device for entering fiction.'

'They were asking me about something like that, now you mention it. It would be very intriguing to try and redevelop it but Polly says I shouldn't. My lab is full of devices, the purpose of which I haven't the foggiest notion about. An ovinator, for example — it's clearly something to do with eggs, but what?'

'I don't know.'

'Well, perhaps it's all for the best. These days I only work for peaceful means. Intellect is worthless if it isn't for the betterment of us all.'

'I'll agree with you on that one. What work were you presenting to MadCon '88?'

'Theoretical Nextian mathematics, mostly,' replied Mycroft, warming to the subject dearest to his heart — his work. 'I told you all about Nextian geometry, didn't I?'

I nodded.

'Well, Nextian number theory is very closely related to that, and in its simplest form allows me to work backwards to discover the original sum from which the product is derived.'

'Eh?'

'Well, say you have the numbers twelve and sixteen. You multiply them together and get 192, yes? Now, in conventional maths if you were given the number 192 you would not know how that number was derived. It might just as easily have been three times sixty-four or six times thirty-two or even 194 minus two. But you couldn't tell just from looking at the number alone, now, could you?'

'I suppose not.'

'You suppose wrong,' said Mycroft with a smile. 'Nextian number theory works in an inverse fashion from ordinary maths — it allows you to discover the precise question from a stated answer.'

'And the practical applications of this?'

'Hundreds.' He pulled a scrap of paper from his pocket and passed it over. I unfolded it and found a simple number written upon it: 2216091 -1, or two raised to the power of two hundred and sixteen thousand and ninety-one, minus one.

'It looks like a big number.'

'It's a medium—sized number,' he corrected.

'And?'

'Well, if I was to give you a short story of ten thousand words, instructed you to give a value for each letter and punctuation mark and then wrote them down, you'd get a number with sixty-five thousand or so digits. All you need to do then is to find a simpler way of expressing it. Using a branch of Nextian maths that I call FactorZip we can reduce any sized number to a short, notated style.'

I looked at the number in my hand again.

'So this is?'

'A FactorZipped Sleepy Hollow. I'm working on reducing all the books ever written to a number less than fifty digits long. Makes you think, eh? Instead of buying a newspaper every day you'd simply jot down today's number and pop it in your Nexpanding calculator to read it.'

'Ingenious!' I breathed.

'It's still early days but I hope one day to be able to predict a cause simply by looking at the event. And after that, trying to construct unknown questions from known answers.'

'Such as?'

'Well, the answer: "Good lord, no, quite the reverse!" I've always wanted to know the question to that.'

'Right,' I replied, still trying to figure out how you'd know by looking at the number nine that it had got there by being three squared or the square root of eighty-one.

'Isn't it just?' he said with a smile, thanking my mother for the bacon and eggs she had just put down in front of him.

Lady Hamilton's departure at 8.30 was really only sad for Hamlet. He went into a glowering mood and made up a long soliloquy about his heart that was aching fit to break and how cruel was the hand that fate had dealt him. He said that Emma was his one true love and her departure made his life bereft; a life that had little meaning and would be better ended — and so on and so forth until eventually Emma had to interrupt him and thank him but she really must go or else she'd be late for something she couldn't specify. So he then screamed abuse at her for five minutes, told her she was a whore and marched out, muttering something about being a chameleon. With him gone we could all get on with our goodbyes.