It all began with a gentle nudge in the ribs, and Mrs Hudson sitting very close to me. She reminded me of all the time she'd brought us milk and bread and other things without which we would almost certainly have perished. And Sherlock, who had previously been in the kitchen, all of a sudden wasn't there anymore. Saw it coming before I did.

What am I talking about? Of course he did.

Anyway, long story short, date cancelled, night spent reading stories to Mrs Hudson's young niece.

Don't ask where she was going. I didn't. I don't want to know. Ask Sherlock. He wasn't there, but I'm sure he'll be able to tell you. Smiling all over her face when she came back and that's all I'm saying. Anyway, she took little Ingrid off my hands and so far as I was concerned the night was over. Had a cup of tea, caught the late news without Sherlock about to turn it over because he predicted it all last century, went to bed.

Best part of the day, frankly.

And I was lying there, just drifting off. That nice little place between being awake and annoyed and the dark below where you're not even dreaming. I was looking forward to that, the dark bit, with no pictures and sounds and nothing to notice and get told off for. It was going to be great.

You'll note the grammar there. The tenses imply that I was defeated in this pursuit. The tenses are, of course, absolutely correct.

So I'm hovering there, waiting for that final last drop into black, when there's a noise through the wall. Nothing major, no gunshots, no explosions, no burglars. None of the stuff I'm almost starting to get used to.

No, this noise was much, much more disturbing than that.

He was laughing. Sherlock, I mean. I hadn't heard him come in, but apparently he was in, and laughing at something.

Two options; get up, get dragged into something, miss out on sleep. Or, and which is the option I eventually opted for, lie completely still, give no indication that I heard him at all, sleep.

This wasn't a selfish thing. If he was laughing, then I knew he was alright. And he owes me so many nights sleep from when he's got a case on. Even if I'm not involved he'll be tromping round the living room half the night and knocking things over and crying out in joy or despair at various experiments. All the usual night noises at Baker Street. And then there's the bloody violin. No, this wasn't a selfish thing. This was just me putting myself first.

Anyway, the laughing had died down.

A few deep breaths, and my mind was blank again. Soft, warm dark was once more waiting beneath me. Just that last little drop out of the conscious world. Just that last and most difficult step to take. Fading out, with my own heartbeat in my ears…

…And then the laugh again.

Up of the dark, an entirely unbidden thought. Nothing to do with my conscious mind, but given to me by the thwarted embers of what would have been a long and uncompromised release; 'There are lots of things in this apartment with which one could kill a man'.

His fault entirely; I never would have had a thought like that when I was in the army. And the army kill people all the time. No, it's only since I ended up here that I've begun to think of pencils as potential deadly weapons.

A pencil might be good, actually.

No. No, I wasn't going to kill him. Like I say, it wasn't even a conscious thought. But I knew in my heart that if the laughter brought me back from the abyss a third time that murder would become a definite option. And getting up, like I explained before, would mean risking everything I currently desired. I.E. sleep. I'm repeating that word an awful lot, I know, but I really can't emphasize enough just how nice it would have been to just bloody sleep.

Being a reasonable man of relatively sound mind, I came to a compromise. I reached up over my head and banged on the wall and shouted at him to shut up.

The door flew open.

So I sat up. And with every millimetre of the movement and every cell of my being I despised him for it.

"John! You're home. What are these, where did these come from, what are they doing here?"

Holding up in his hand, like giant playing cards, soft skinny books with colourful covers.

"They're… Sherlock, they're picture books. Mrs Hudson's niece must have left him. Thanks for that, by the way, leaving me with that. Where have you been since four o'clock?"

"Oh, that's what it was. I thought the latest girlfriend just wasn't wearing perfume. I wondered, actually, where the smell of cola cubes was coming from. But John, that's not important. These, these books, John, these are important."

"No they're not, they're picture books."

I was trying, by this stage, to get a good look at his eyes. They were wide and wild, of course, as they always are when he gets these little fits of excitement. And yet the pupils seemed no more dilated than the dim lights in the room would demand. Which couldn't possibly have been right, because that would have meant he was getting this excited about The Gruffalo without so much as a Bacardi Breezer in him.

"See, this is why I left the babysitting to you, John, it's so much more your level."

And at that he threw himself into the chair in the corner and oh look, flying out that open window, is that my chance of a decent night's sleep? Why, yes, I think it is. Oh well. Goodbye, Mr Sandman, maybe another time, hm? Do call back again, won't you…

I'm not a bitter person. Usually.

He skimmed one of the books, Frisbee-style, over the bed to me.

"Look at that book, John, tell me about that book."

And he sat there grinning. Announcing without a word that he wasn't going anywhere until I played along. "It's… It's I Want My Hat Back. It's about a bear who's lost his hat and he asks around and he gets it back."

"Ah, but John, John, you're missing the key point, all the beauty of it! One of the suspects the bear interviews in his pursuit of said hat is in fact wearing the hat at the time. He only realizes later that his hat was in front of him!"

"No, no, Sherlock, the bear doesn't interview any suspects; he asks his friends about his hat. It is a children's book."

"But that's exactly the point, it is not!"

He declared this in the exact tone that I know him to use in declaring the solution to any great mystery. Murders and thefts and disappearances, and the bear's hat.

And he was waiting for me to ask, so I asked, "What is it then?"

"It is, John, Poe's Purloined Letter."

The Edgar Allen Poe story, The Purloined Letter, has plot similarities with Jon Klassen's I Want My Hat Back. That was what he'd wakened me to tell me.

No, sorry, not wakened. I wasn't asleep yet. No, what Sherlock did was worse. He denied me any sleep at all. Over a book about a bear and a hat.

A bear, dear reader, and a hat.

"Well?" he said. I had been too busy determinedly not reacting to react, and so he thought I was ignoring him. "Think about it! It's the sublime within the ridiculous, one of the first and most accomplished detective stories boiled down to its simplest form, to a bear and a hat, to a children's book! Isn't it beautiful, John?"

It's a bear and a hat, Sherlock.

That's what I wanted to say. I didn't. He only would have tried to explain again. So I nodded. And I think he took all the blank staring for shock, for the gaze turned inward, chiding myself for my own stupidity, stunned by my own blindness that I hadn't noticed it sooner.

But that only gave him licence to move on to his next piece of evidence. He held up another book, like a teacher with a flashcard. Almost shaking with the greatness of this discovery, that children's books have plots, willing me to get it right, he presented me with the cover.

"That, Sherlock," I said, "is The Gruffalo."

"Ah," he said, "But what did it used to be, John?"

"…The Great Gatsby?"

"You're being sarcastic, I appreciate that, but that, in fact, is not a bad guess." He looked at me a while. Maybe he thought I was taking him seriously, though I have no idea what would have given him that impression. I think he expected me to guess again. So I shrugged and passed it over to him.

"It's Highsmith's Talented Mr Ripley, John. The Little Brown Mouse gets caught in his own lies and unwittingly creates his own monster, but then is able to use the web that threatens to destroy him as his ultimate salvation! It's all there! The fox, the snake and the owl representing Dickie, Freddie and Marge, the Gruffalo itself as Tom's own schizophrenic genius! It's an amoral parble, an anti-fable. It's certainly not suitable for children, John."

And I had an idea then.

The kind of obtuse, human idea that would probably never occur to him, and this, perhaps, is why he didn't suspect.

I said, "That can't be right. No, sorry, Sherlock, I don't believe you."

This with near-biblical fervour; "But it's true, John! It's all here! Here with knobbly knees and turned-out toes and a poisonous wart on the end of its nose!"

"No, I'm sorry, I just don't buy it. I mean, if you can prove it to me, go ahead, but for now, I just don't-"

He got all affronted then, sulking down in the chair. Right where I wanted him.

See, I can be smart too sometimes.

"Prove it to you, is it? Fine."

And sitting there, sulking right down low, he opened the book and propped it up on his stomach. Blocking his view of me. Very slowly, very quietly, I lay back down and pulled the pillow in beneath my head, shifted the covers up to my shoulders.

And I was sinking again.

And he began, in the low, even and above all comforting voice of a man who seeks to present nothing but the simple facts in front of him, "A mouse took a stroll, through a deep dark wood…"