I pulled myself up, noting with little interest that my head was an inch away from the edge of the curb stone. I was in the gutter amongst the soggy leaves. It was raining.

I blinked. I was in Cambridge Road and - oh joy - there were cars parked in front of the houses. There were telephone wires and satellite dishes, electric lights and traffic jams. The air was polluted by SO2 and CO4, not sewage and horses. There was a plane in the sky. Things were prosaic, mundane and ugly. Wasn't it wonderful?

I lurched to my feet, happy to discover I was cold, covered in leaves, missing my scarf, and none the worse for any of it. I walked slowly out of Cambridge Road, thinking of my pointless request. Write to me. Ye gods.

Stupid. So stupid. The Post Office go by numbers corresponding to addresses, not years.

I stopped by the bookshop, and on a whim since it was open, entered. It was the kind of pokey old shop where the keeper is a real bibliophile and will do everything within his power not to sell or part with any of his beloved books.

"Can I help?" a grizzled, bespectacled but clear-eyed man behind the desk asked.

"Um, just looking..." I glanced at the numerous and bulging shelves. "Actually, do you have any fiction?"

"Yes, who by?" The man had stood up and was fumbling to put on his glasses.

"By Sir Arthur Conan - no, wait. Do you have any books written by Dr Watson?"

The man stopped and stared at me. Finally he removed his glasses and began to polish them absently. He was obviously thinking. He seemed to reach a decision. "Would you wait here a moment, please?" He disappeared into an adjoining room, also full of dusty books. I waited. After some minutes he returned with a carefully wrapped parcel under his arm and a letter or note of some kind. "Took me a while to remember," he explained, "and another while to find it. Could I take your name?"

I was a little confused. Buying a book did not usually require name rank and number. "Morrison. Um. Emma."

He looked excited for some reason. "Morrison! This is for you then, this is yours..." he added, waving the package at me. "I suppose one should ask for ID but there's no way you could have known about it..."

I had no idea what he was talking about. "I haven't got any money with me at present..."

"No, no, no, there is no charge, this was paid for a long time ago, and quite handsomely I believe, for the time."

I took the parcel and then looked at him stupidly. "I, uh, I don't understand."

"This book shop," he explained, "was here before the 1900s. My brother bought it in the '70s, but there were some rather peculiar conditions in the contract that went with it. Namely, a package that was to be delivered to its named recipient - but not before 2009. It was, we have been told, a book and already paid for. It was not to be sold or given to anyone else. It's was all set out in a letter, signed by a Dr Watson." He smiled. "Finally got it to the right person, as requested. Would you mind opening it here? I know it's your business, but I've always wondered what it was..."

"Yeah, sure. Have you got any scissors?" I lay the package on the desk, and waited as he found me a penknife to cut the twine.

I unwrapped it.

Bound exquisitely in dark leather was 'The Sign of Four' by Sir Arthur Conan Doyle, as well as a letter neatly addressed to Miss Morrison.

"That's a beauty," murmured the shopkeeper, looking at the front page. "Ah, a Sherlock Holmes story gifted by a Dr Watson – very droll to play on the coincidence. First edition. 1890. Pages uncut too!" He laughed. "Not for sale is it?"

I shook my head possessively. "Not a chance!" I wrapped it up carefully again. "Um. Thank you."

"Thank you. Glad to get it off my mind – it's been sitting in the safe for as long as I can remember! A real mystery. We knew it was a book of course, but it was all just such a peculiar song and dance..." He was looking at me with a hopeful and slightly hungry expression, in desperate need of an explanation but too bemused and polite to demand one.

"It was, uh, a sort of literary treasure hunt. Thomas Carlyle was my however-many-greats grandfather. He started the game - a quest really - with his daughters and it still crops up as a family tradition with Christening gifts and legacies and such. This was the last unclaimed prize."

He raised his eyebrows at me, game but uncertain, just like my explanation.

"I'm awfully good at crosswords," I lied with enthusiasm as if that cleared up everything. (Incidentally, the bit about me being related to Carlyle is actually true, but the rest was flimsy invention.)

Thankfully the bibliophile was too caught in the situation to really argue. He was almost chuckling to himself. "I'll have to phone my brother to tell him – legacies and treasure hunts, eh? ... Aren't you cold with no shoes on?"

I laughed, thanked him again, and scarpered.

Before I got home, I stopped at a telephone box and called Siân on reverse charges, begging her to be my alibi for the last day and night. She agreed readily enough and, being Siân, didn't ask for a reason, knowing she would get the full explanation when I gave it.

Of course as soon as I went into the house, I walked straight into another argument with parents hungry for answers. But Siân was as good as her word, my alibi held and I apologised to everyone profoundly, blaming my behaviour on stress and general stupidity.

The only other point of interest is the fact that on the inside cover of the book was written,

I thought my scribing fact,

Holmes proclaimed it romanticism

and you swore it was fiction.

Perhaps in this case they are all one and the same?

J H Watson MD.

That, and of course, the letter.

Miss Morrison,

Having been made aware of my friend's forthcoming publication, I thought it an excellent time to write to you. It has been almost two years now since you visited us at Baker Street and vanished from our sight in Cambridge Road.

I believe I am right in saying that your case is the only one in my career so far, that was, and still is, completely mystifying. Neither Dr Watson nor myself could find the reason for your experiences, but, as I frequently remind Watson, life is infinitely stranger than anything which the mind of man could invent.

I have taken some care that this book and my letter should reach you. I would like to thank you for the information you gave me concerning Professor Moriarty. In view of the nature of your departure, I am aware your story may hold both truth and merit.

Watson has declined to chronicle your case, although he tells me he has spoke about it to his friend, Wells.

You don't mind if I make use of your scarf, I trust? Mine was the unfortunate victim of a chemical experiment that went awry.

I hope this letter finds you in the best of health, and believe me to be, my dear young lady,

Very sincerely yours,

Sherlock Holmes.