John was just finishing his breakfast when Sherlock came into the kitchen, looking somewhat distracted.

"Have you seen my diary, John? I can't remember which of my nemeses I'm supposed to be meeting this morning."

John furrowed his brow quizzically. Again.

"Nemeses?"

"Yes. You know – these horribly damaged, yet brilliant, criminal masterminds I keep meeting to whom I feel strangely drawn because they're the one person in the whole world who knows what it's like to be as clever and sociopathic as me. The trouble is, I've collected quite a few of them now and I'm starting to get them mixed up. Now, who is it this morning?"

A worried flicker crossed his face.

"It's not my brother, is it?"

John, who had by now found Sherlock's appointments diary and had flicked to the relevant page, shook his head.

Sherlock breathed a sigh of relief.

"So who is it then? The cab driver? No, you killed him, didn't you? Moriarty?"

"Er, actually, it's Irene Adler."

"Who?"

"Irene Adler?"

"Hmm…it's ringing a bit of a bell, but the trouble is, there are just so many of these people who are the only person in the world like me, I lose track. They're starting to outnumber the normal people…."

"She's a lesbian dominatrix," John prompted, helpfully.

"A lesbian dominatrix, eh? A dominatrix who only has female clients?"

"Well, no," clarified John. "She's a unisex lesbian dominatrix."

"Ah! So she has sexual encounters with men, as well as women, for money, but she only falls in love with women?"

"She's in love with you, Sherlock."

"Oh." His mercurial brain didn't take long to leap to a razor-sharp deduction. "So I'm a woman, then?"

John shook his head.

"No, you can't be a woman, Sherlock, because I'm in love with you."

"Right." Sherlock was beginning to feel a bit at sea with all this, but he was determined to muddle his way through the confusion. "So you're gay?"

"Oh, no! I'm straight."

"I have to admit, John," Sherlock confessed, at last, "I'm not completely following the logic here."

"Oh," John raised an eyebrow in surprise, "so there are some things which are beyond even your ken?"

"Hang on a minute…" murmured Sherlock, running his hands through his hair, "Ken….Ken….No, I don't think I know him. Who's he in love with?"

"Mrs Hudson."

"So he's gay?"

John grinned. "I knew you'd start to get the hang of this eventually."

At that moment, they were interrupted by the sound of a toilet flushing, which freaked them out a bit, as they had thought they were the only people in the house. John had started to reach for his gun, when a startlingly beautiful woman emerged from the toilet, dripping water onto the carpet and stark naked. She posed provocatively in the doorway.

"Irene!" John moaned. "Did you have to swim into the house through the toilet? I'd only just mopped the bathroom floor! Can't you just use the front door like everyone else?"

Irene smiled enigmatically. "Where would be the challenge in that?"

"Didn't you get some funny looks coming here on the bus like that?" asked Sherlock, gesturing at her naked form.

"Not really," she purred, seductively. "But, without pockets or a handbag, I did have to come up with some imaginative ideas of where to put my Oyster card."

"Hmm…" responded Sherlock, in a studiedly cold fashion that gave nothing away, as he ushered his visitor to the sofa. "John? Do you think you could possibly make a cup of tea for Irene and I?"

"OK," sighed John, in his martyrish, put upon way, as he began to make his way to put the kettle on. But then something brought him up short. He turned back to his flatmate, flabbergasted.

"Sherlock? What on earth's happened to your grammar?"

"I don't know," said Sherlock, looking worried, "but whomever writ my last sentence should of been hung…Oh, God!" He broke off in horror, not daring to say a word more, lest he begin to sound more and more like a semi-educated middle manager from Essex.

It was most peculiar. But they didn't have time to ponder this, as, at that very moment, a group of heavily armed commandos in black, toting sub-machine guns, burst into the room, grabbed John and Irene and, after a short struggle, held them at gunpoint. Their leader, a short, stocky, grey-haired man, stepped forward and smiled malevolently.

"Sherlock Holmes!" he snarled, in a vague approximation of an American accent, which immediately told Sherlock that he was from the CIA. "This woman…" he jabbed a chubby finger at Irene… "has something on her 'phone which my employers need. You are the only person clever enough to work out the code to unlock it. You will do so within the next ten seconds, or we will blow the heads off the two people you love most in the world!"

Sherlock was now completely confused. So he was apparently in love with Irene, which meant he was gay, but at the same time he was also in love with John, which meant he was straight. How could this be?

"John?" he called over, to where a burly commando had his friend in a half-nelson with a submachine gun pointed at his head. "I'm in love with a man AND a woman, so that makes me…?"

"Asexual," John answered, though he could hardly breathe.

"OK. So that's that sorted out. Thanks!"

The scary, grey-haired CIA agent was now beginning to get very impatient and started to count down from ten. Sherlock didn't have long to formulate a plan. It took some thinking, and the man had already got down to "one and a half, one and three eighths, one and a quarter…" when Sherlock attempted a desperate gambit.

"All right!" he said, holding his hands above his head, to show he was unarmed. "I can see that you've got me entirely over a barrel here. I have no choice. I have to do exactly what you say and recognise that I have no bargaining chips and no room for negotiation, whatsoever. So, I tell you what, if you send all these armed men out of the room, put them on the first train to Stockton-on-Tees, so they're unable to come back and give you any armed back-up, and then throw your own gun out of the window, I'll agree to help you. How about it? Can't say fairer than that, can we?"

The scary, grey-haired CIA agent thought about it for a moment and then nodded.

"OK," he said, disarming himself and then dismissing his heavies with a brisk gesture.

Sherlock waited until the commandos were long gone before breezily adding, "Oh, and, while you're at it, I don't suppose you'd mind binding your own mouth and feet with duct tape, handcuffing your hands behind your back and then going and sitting on that window sill up there? Close to the edge?"

The scary, grey-haired CIA agent smiled co-operatively, already moving in the direction of the window. "Sure! I'd be happy to help!" He began to busy himself with duct tape and electrical cord and was soon completely absorbed in his task.

While he was getting on with that, John decided to go back to putting the kettle on.

Irene produced her mobile 'phone – the new high-tech PaTensing brand, with a prominent logo just beneath the screen – from one of her orifices and amused Sherlock by getting him to try to guess what the four-letter pin code was. ("I'll give you a clue! It's a very bad pun!")

He still hadn't guessed 50 minutes later, when they heard footsteps on the stairs.

"Cooee!" called a fragile, nervous voice. "I hope you don't mind me coming up without knocking, but the door was open…"

Molly appeared at the top of the stairs, but narrowed her eyes in jealousy when she noticed the naked Irene sitting next to Sherlock on the sofa.

"Ah, Molly!" Sherlock muttered, wondering how best to defuse the situation. "I don't think you've met Irene, have you? You'll like her. She's a lesbian dominatrix. In fact…" (he winked suggestively) "…I think you'll like her a lot!"

"But I'm not gay!" protested Molly.

"Oh," Sherlock smiled, a somewhat patronising look on his face, "I think you'll find you are. After all, you're in love with me."

"Sherlock," John asked in amazement, "is there anyone, anyone at all, who isn't in love with you?"

"Hmm…." Sherlock mulled it over.

He observed the red roses on the mantel piece which had come from Anderson, the love letter on the kitchen pinboard from Mike Stamford, the romantic chocolates which Clara had had FedExed to him. He glanced over at the window sill where the, by now bound and gagged, scary, grey-haired CIA agent was, despite his bonds, still managing to write "SH 4 SGHCIAA True!", surrounded by a soppy love heart, in the condensation on the window.

"Actually, no," Sherlock blushed. And then, after a pause, "I think that, perhaps, it might be the coat."

"Oooh!" Molly squealed excitedly as her eyes alighted on the scary, grey-haired CIA agent bound and gagged on the window sill. "I see you've got a scary, grey-haired CIA agent bound and gagged on your window sill. Would you like me to push him out of the window for you?"

"No," Sherlock decided, magnanimously. "Not pushing him out of the window would be a nice little gesture to demonstrate how much my character has grown and humanised since series one. And, anyway, it is Christmas, after all!"

"Is it?" Molly asked, frowning.

Sherlock gestured towards the window.

"Hadn't you noticed? It's snowing."

Molly turned to look for herself and her puzzlement deepened.

"But we don't normally get snow in London at Christmas!"

"We do now!" smirked Sherlock.

"Is it global warning?"

"No, actually, I think it's just a lazy and rather ill-thought-through visual cliché," he reassured her, as they both moved towards the window to watch the snowdrifts piling up down Baker Street and the people walking through it with completely dry umbrellas. A cluster of carol singers in Victorian dress began to assemble round an old-fashioned gas lamppost and, not long after, Sherlock and Molly saw Tiny Tim walk past, struggling under the weight of a large goose.

"Ah, well" sighed Sherlock, at length. "I suppose it doesn't matter for the PBS audience: I mean, most Americans probably don't know about typical London meteorological patterns."

"Oh. Oh, yes!" Molly giggled. "Of course! Silly me! The PBS audience! I suppose that's why I've stopped working in a mortuary and am now working in a morgue."

John grinned straight to camera.

"Don't worry!" He threw in a saucy wink. "I won't be having any more ASBOs, either, this series…I mean, season. I know you don't know what they are!"

Sherlock shook his head, sadly.

"At this rate, if we run to a third series, I'll be living in an 'apartment' and asking John to get me a 'soda' out of the 'ice-box' while I 'call' Moriarty on my 'cellphone'!"

There was silence for a moment and then an idea occurred to him.

"Hmmm. I wonder."

"What is it?" asked Molly.

"Well," said Sherlock, "now that me and John are an internet sensation, it shouldn't be too hard for us to find Steven a Britpicker for Christmas (even though he's already British)….er…John and me? John and I? John and myself?..."

"And a SPAG beta!" added John.

"So," said Sherlock, much cheered, turning to Molly, "Merry Christmas, Molly Hooper!"

And, to her obvious delight, he gave her a kiss on the cheek.

Then he went to kiss John.

"Merry Christmas, John Hamish Watson!"

Then he kissed Irene.

"Merry Christmas, Irene Adler!"

Then he kissed the scary, grey-haired CIA agent.

"Merry Christmas, scary, grey-haired CIA agent!"

Then he kissed his brother, who had just appeared at the top of the stairs.

"Merry Christmas, Mycroft Holmes!"

And, at that moment, an instrumental version of "We Wish You A Merry Christmas" began to blare out across the room, from no obvious source.

"Ah!" cried Sherlock, rubbing his hands in glee. "Violin music. Excellent! Now, who wants to watch me doing some highly unconvincing miming?"