I will admit that I would probably have gone to great lengths to include a Sherlock Holmes story in this series, but thankfully I don't have to. Go to great lengths, that is: The perfect story is right there in the very first collection, The Adventures of Sherlock Holmes (1892). It is titled "The Adventure of the Blue Carbuncle" (which, I grant you, does not automatically scream Christmas, but stay with me) and was first published in The Strand Magazine in January 1892.

An American publication gave it the title "The Christmas Goose that Swallowed the Diamond," which is a little more festive; but I feel that rather gives the game away too early. Pretend I did not mention that.

It opens in 221B Baker Street, as so many Sherlock Holmes stories do, even though Watson has actually moved out at this point in order to marry the most insipid woman in literature (that may be an exaggeration, but probably not).

I had called upon my friend Sherlock Holmes upon the second morning after Christmas, with the intention of wishing him the compliments of the season. He as lounging upon the sofa in a purple dressing gown, a pipe-rack within his reach upon the right, and a pile of crumpled morning papers evidently newly studied, near at hand. Beside the couch was a wooden chair, and on the angle of the back hung a very seedy and disreputable hard felt hat, much the worse for wear, and cracked in several places.

I rather think the second morning after Christmas is a little late for Watson to pay Holmes a Christmas visit; but don't mind me. This is a classic opening, in a way. Not only the location, but the opportunity for a minor bit of deduction before the main mystery begins. Holmes' relaxed pose and the suggestion of clutter is also not out of the ordinary (there is a wonderful description of the chaos that is this corner of Baker Street in the opening of "A Scandal in Bohemia" (which, if you haven't read it, I have no idea what you have been doing with your lives), which endeared Holmes to me early on).

I seated myself in his armchair, and warmed my hands before his crackling fire, for a sharp frost had set in, and the windows were thick with ice crystals. 'I suppose,' I remarked, 'that, homely as it looks, this thing has some deadly story linked on to it -- that it is the clue which will guide you in the solution of some mystery, and the punishment of some crime.'

Dr Watson is unusually right here: While he is apparently quite wrong, as usual, the hat does lead them to crime, eventually. There is, however, no foundation for that deduction yet, and Holmes, who can usually spot the crime in the most innocent-looking circumstances, is apparently in a very mellow mood.

'No, no. No crime,' said Sherlock Holmes, laughing. 'Only one of those whimsical little incidents which will happen when you have four million human beings all jostling each other within the space of a few square miles. Amid the action and reaction of so dense a swarm of humanity, every possible combination of events may be expected to take place, and many a little problem will be presented which may be striking and bizarre without being criminal.'

This would not be altogether unusual, however; as both Holmes and Watson observe in this story, quite a few of their adventures. Unlike Agatha Christie, whose stories generally revolve around murder, Doyle wrote a number of quite bloodless plots, sometimes quite quite innocent resolutions ("Whisper Norbury in my ear" etc).

The hat, we are told, arrived on Christmas morning, together with a fat goose, which the commissionaire who brought both has taken away to eat. He had seen a group of ruffians attack the man with the goose. In the scuffle, he (the man with the goose) lost his hat and accidentally broke a window, and when he saw an official-looking person hurrying towards him (to his aid), he misunderstood, dropped the goose and ran off. While they can be fairly sure the man's name is Henry Baker (because of a note on the goose and initials in the hat), it is not so easy to find one among many such in London in order to give the goose back. Hence Holmes' contemplation of the hat. He urges Watson to have a look at it, and when Watson claims to see nothing, we get a variation on the classic "you see, but you do not observe":

'On the contrary, Watson, you can see everything. You fail, however, to reason from what you can see. You are too timid in drawing your inferences.'

Holmes, however, has never been timid:

'That the man was highly intellectual is of course obvious upon the face of it, and also that he was fairly well-to-do within the last three years, although he has now fallen upon evil days. He had foresight, but has less now than formerly, pointing to a moral retrogression, which when taken with the decline of his fortunes, seem to indicate some evil influence, probably drink, at work upon him. This may account also for the obvious fact that his wife has ceased to love him.'
'My dear Holmes!'
'He has, however, retained some degree of self-respect,' he continued, disregarding my remonstrance. 'He is a man who leads a sedentary life, goes out little, is out of training entirely, is middle-aged, has grizzled hair which he has cut within the last few days, and which he anoints with lime-cream. ... Also, by the way, that it is extremely improbable that he has gas laid on his house.'
'You are certainly joking, Holmes.'

Watson's lack of faith is of course disturbing, and if you feel similarly inclined I suggest you get a hold of the story here for the full deduction (or abduction!). Here is a sample, however:

'But his wife -- you said that she had ceased to love him.'
'This hat has not been brushed for weeks. When I see you, my dear Watson, with a week's accumulation of dust upon your hat, and when your wife allows you to go out in such a state, I shall fear that you also have been unfortunate enough to lose your wife's affection.'

The plot thickens, though (as plots tend to do): The commissionaire comes running back, clutching a blue stone that "twinkled like an electric point in the dark hollow of his hand", saying that it was inside the mystery goose. Holmes, having just read the papers (evidence of which is scattered all over 221B), recognises it:

'It is more than a precious stone. It is the precious stone.'

Which is to say, it is the blue carbuncle, stolen from the Countess of Morcar at the Hotel Cosmopolitan on the 22nd of December. While not very big, it is marvellously rare (which it should be, as carbuncles are always red). Jack Horner, a plumber who has previously been convicted of robbery has been arrested, but claims to be innocent. In order to find out whether Mr Henry Baker had anything to do with it, Holmes advertises the find of a hat and a goose. And Baker arrives (wearing a Tam o' Shanter, because he has lost his hat, and no respectable man will leave the house with his head uncovered), confirming all of Holmes' deductions about him (with the possible exception of whether his wife loves him -- though I assume losing the Christmas goose did not help with that). Holmes tells him that

'By the way, about the bird -- we were compelled to eat it.'
'To eat it!' Our visitor half rose from his chair in his excitement

But when he is offered another goose instead, he accepts without protest -- thereby proving himself innocent. He also tells them where he got the original goose: an inn, where there was a goose-club (nothing sinister: You pay a few pence every week, and then you get a goose for Christmas). He also thanks them for the return of his hat:

'I am much indebted to you, sir, for a Scotch bonnet is fitted neither to my years nor my gravity.'

(Which, to be fair, is true for most people.)
The trail takes them from the inn to a Covent Garden salesman, who turns out to be particularly tight-lipped (mainly because he is fed up with people, and in particular people talking about geese, which I suspect is an unfortunate condition to be in for a person selling geese at Covent Garden).

'it's "Where are the geese?" and "Who did you sell the geese to" and "What will you take for the geese?" One would think they were the only geese in the world, to hear the fuss that is made over them.'

Holmes is a sneaky connoisseur of human nature, however, and bets that the birds were country bred; to prove him wrong, the salesman tells him exactly where they came from: a Mrs Oakshott. As they stand laughing to themselves over how easily someone who would not give the information for a hundred pounds is quite thrilled to provide it for a pound if in the shape of a wager, another man comes along to aggravate the salesman, finally tipping him over the edge.

'I've had enough of you and your geese,' he shouted. 'I wish you were all at the devil together.'

The man who has clearly pushed the salesman beyond all boundaries turns out to be John Ryder, whom Holmes identifies as the head attendant at the Hotel Cosmopolitan. He takes him back to Baker Street to confront him, whereupon Ryder makes quite a poor showing by almost fainting into the fire, and after a bit of brandy deciding to beg very persistently for his life and liberty. Holmes comments that

'He's not got blood enough to go in for felony with impunity. Give him a dash of brandy.'

It turns out Ryder is the brother of Mrs Oakshott, and that she had promised he could pick the goose he liked for Christmas. And, desperate for a hiding place for the carbuncle after the theft, he shoved the stone down its throat. He is interrupted by his sister, but in the end she allows him to kill the bird and take it with him immediately. In the confusion, however, he has taken the wrong bird, leaving the right one to be sold to to the Covent Garden salesman, who sold it on to the Inn with the goose-club, who eventually gave it to Henry Baker. Ryder is understandably rather annoyed to now be facing jail for the theft of riches he did not even get to enjoy, and he pleads his case quite pitifully. Possibly disgusted by it all, Holmes tells him to get out.

'After all, Watson,' said Holmes, reaching up his hand for his clay pipe, 'I am not retained by the police to supply their deficiencies. If Horner were in danger it would be another thing, but this fellow will nto appear against him, and the case must collapse. I suppose that I am commuting a felony, but it is just possible that I am saving a soul. This fellow will nto go wrong again. He is too terribly frightened. Send him to gaol now, and you make him a gaol-bird for life. Besides, it is the season for forgiveness.'

As Richard Lancelyn Green observed in his notes to the Oxford edition of the stories, however, Holmes was not commuting a felony at all (only the Crown can do that); he was, however, compounding it by (presumably) taking a reward without prosecuting the person who had committed it, which apparently made him guilty of "misprision of felony". But since Dr Watson is not likely to tell anyone (except the whole world), Holmes is probably safe. To round off the tale, they sit down for "another investigation, in which also a bird will be a chief feature". And all is well.