Opening Passage: From "The Empty House", as is only fitting:
It was in the spring of the year 1894 that all London was interested, and the fashionable world dismayed, by the murder of the Honourable Ronald Adair under most unusual and inexplicable circumstances. The public has already learned those particulars of the crime which came out in the police investigation, but a good deal was suppressed upon that occasion, since the case for the prosecution was so overwhelmingly strong that it was not necessary to bring forward all the facts. Only now, at the end of nearly ten years, am I allowed to supply those missing links which make up the whole of that remarkable chain. The crime was of interest in itself, but that interest was as nothing to me compared to the inconceivable sequel, which afforded me the greatest shock and surprise of any event in my adventurous life. Even now, after this long interval, I find myself thrilling as I think of it, and feeling once more that sudden flood of joy, amazement, and incredulity which utterly submerged my mind. Let me say to that public, which has shown some interest in those glimpses which I have occasionally given them of the thoughts and actions of a very remarkable man, that they are not to blame me if I have not shared my knowledge with them, for I should have considered it my first duty to do so, had I not been barred by a positive prohibition from his own lips, which was only withdrawn upon the third of last month.
Summary: If we look at Sir Arthur Conan Doyle's list of favorite Holmes stories, he gives four from The Return of Sherlock Holmes: "The Dancing Men" (#3, due to originality of plot), "The Empty House" (#6, for the obvious reason), "The Second Stain" (#8, with "The Naval Treaty" among the best of the series but a better story than the latter), and "The Priory School" (#10, for the scene in which Holmes points his finger at the Duke). No doubt Doyle is partly trying to make sure his list has variety, but "The Empty House" and "The Dancing Men" consistently make lists of fan favorites, and are probably the only Return stories to do so, and while all the Return stories have their interesting points, "The Second Stain" is easily the most cleverly structured, with its interwoven double-layered mystery to match the two layers of official police and above-official diplomatic intelligence, and for the most striking twist it's a choice between "The Priory School" and "Charles Augustus Milverton". Most of the other Return stories have, despite their experiments in putting Holmes in different situations, a pedestrian feel, or perhaps 'episodic' would be better for the television age, since they are a bit mystery-of-the-week; the most obvious example being "The Three Students", which I think works very well as an example of the puzzle-fiction branch of detective fiction, but wouldn't be much different in character if the detective were not Holmes but Encyclopedia Brown. In any case, "The Empty House" is obviously the story that has to be looked at, "The Dancing Men" is obviously the one most people find most memorable, and "The Second Stain" is the one I looked at adaptations for (and provides a suitable bookend to "The Empty House").
"The Adventure of the Empty House", of course, brings Sherlock Holmes back by establishing that he did not in fact die at Reichenbach Falls. Three years have passed since that fateful day, and in March of 1894 an extraordinary murder happens: behind locked doors, Ronald Adair is killed, with no obvious way for the murderer to have escaped. Watson, who due to his past association with Holmes takes an interest in cases he thinks his deceased friend might have found worthwhile, visits the scene of the crime, but when there runs into an angry elderly book collector. The book collector visits him again later, and it turns out to be Sherlock Holmes in disguise. Holmes has been pretending to be dead for the past three years in order not to be killed by the remnants of Moriarty's organization, and he is almost at the end of that tunnel -- Holmes finally sees a chance to take down Colonel Sebastian Moran, the last of Moriarty's right-hand men. With the help of Inspector Lestrade, Holmes and Watson will find a way to hold him accountable for his most recent murder, that of Ronald Adair.
As retcons go, "The Empty House" is, I think, moderately successful. The account of Holmes's survival is not particularly plausible, nor is the account Holmes gives of how spent the next three years, which requires us to believe that he has been traveling to places with misspelled names and is apparently, and completely unexpectedly, fluent enough in Norwegian to have been able to become, also completely unexpectedly (and a little oddly, given that he's trying to keep a low profile), internationally famous as a Norwegian explorer. Perhaps the charitable reading there is that Watson is deliberately changing details, and signaling that he is doing so, in order to protect either the innocent or government secrets, which we know from other stories he occasionally does. However, the idea that Moriarty's end doesn't mean the end of his dangerous organization is a shrewd one, and it is plausible that, despite Holmes's efforts in "The Final Problem", some of Moriarty's gang might slip through the nets due to happenstance and luck. And perhaps more important, Colonel Moran provides a sufficiently exciting spark to light the new fire.
"The Empty House" is nominally a locked-room mystery, although the locked-room takes backseat to the re-introduction of Holmes. "The Adventure of the Dancing Men" is a different genre of detective fiction altogether, being a cryptographic mystery. Cryptographic mysteries are by their nature tricky, because you need a code or cipher that is challenging to make your detective look intelligent but easy enough to give the interested reader a chance to match wits with them and try to solve it first. "The Dancing Men" is a relatively successful example of the genre -- the cipher itself is a relatively straightforward substitution cipher, and Holmes himself solves it with elementary frequency analysis. But the cipher itself is, I think, well done -- it's different enough that you could see why someone would not recognize it as a cipher, which goes a long way to making Holmes seem clever in catching the point at once. Hilton Cubitt has recently married an American woman, Elsie Patrick; he knows, without knowing the details, that she is running from some dark secret in her past. Recently it has become clear that the trouble is catching up to her, as she starts acting differently upon receiving messages containing little dancing stick-figure men. Holmes, of course, can solve the riddle, but he is coming into the puzzle late in the game, and time is running out.
"The Adventure of the Second Stain" is Doyle's second attempt to put Holmes to rest. In "The Adventure of the Naval Treaty" in the previous series, Watson had mentioned a case by this title, and then goes on to say of it:
The first of these, however, deals with interest of such importance and implicates so many of the first families in the kingdom that for many years it will be impossible to make it public. No case, however, in which Holmes was engaged has ever illustrated the value of his analytical methods so clearly, or has impressed those who were associated with him so deeply. I still retain and almost verbatim report of the interview in which he demonstrated the true facts of the case to Monsieur Dubugue of the Paris police, and Fritz von Waldbaum, the well-known specialist of Dantzig, both of whom had wasted their energies upon what proved to be side issues. The new century will have come, however, before the story can be safely told.
"The Second Stain" explicitly refers back to this, so it is intended to be the promised story. However, the story we actually have only has a few features. It is a matter of importance, but we have no reason from the story itself to think that it implicates many of the first families of the kingdom; the French are indeed investigating a side issue, but it seems implausible given the story that we have that Holmes would have told any police, much less foreign police about the letter. Holmes does impress the prime minister and some others by rediscovering a lost letter, but not in a way that exhibits his analytical method; indeed, the only people who know about how Holmes knew where to find the letter are Holmes, Watson, and the thief. So by "those who were associated with him" no one could possibly be meant except Watson himself!
Regardless, "The Second Stain" takes us into yet another branch of detective fiction, espionage mystery. An important diplomatic letter has been stolen, nobody knows how. It must be kept secret, even from the police. Holmes is engaged to discover the culprit, and as he is investigating it intersects with a police case, the murder of Eduardo Lucas. By putting the two together, Holmes is able to trace the matter back to the culprit.
"The Second Stain" is very adaptable tale, with a high-stakes plot and a lot of room for adding a little extra excitement if you need to do it. I listened to the 1940 radio adaptation in The New Adventures of Sherlock Holmes, with Basil Rathbone as Holmes. the 1954 radio adaptation in The Adventures of Sherlock Holmes, with John Gielgud as Holmes; Gielgud was only Holmes for a few months, but "The Second Stain" is one of the ones he did. I also watched the 1986 TV version, with Jeremy Brett as Sherlock Holmes. And for good measure, I watched the episode, "The Adventure of the Second Stain", from the animated series, Sherlock Holmes in the 22nd Century, with Holmes voiced by Jason Gray-Stanford. All of them were remarkably faithful -- they emphasized different things, and they added things of their own, and of course the last of the four was a much freer adaptation than the other three in order to include the science fiction elements (it also simplifies the blackmail issue), but it is, as I said, a very adaptable tale. Unsurprisingly the TV episodes add more physical activity. The primary differences were in the Holmeses; Gielgud's comes across as relatively quiet while the other three are much more rambunctious. Brett's comes across as more vain and yet also lighter-hearted than the other three. And in terms of how they were written, the 22nd Century Holmes is much more concerned with upholding the law than the other three are. All of them are good, though, even the animated one; Sherlock Holmes in the 22nd Century episodes are very uneven, with some decent and some schlocky, but "The Adventure of the Second Stain" is probably one of the best episodes.
My overall impression of The Return is that here we begin to have a Holmes whose relation to the law is much, much looser than in the previous series. Obviously, he's been pretending to be dead in "The Empty House", even to the police. "The Norwood Builder" opens with Holmes remarking that London has become boring without Moriarty. In "The Dancing Men", Holmes is annoyed to be misidentified as a police detective. In "The Priory School", Holmes helps with a cover-up. In "Charles Augustus Milverton", Holmes deliberately engages in burglary and remarks, "I have always had an idea that I would have made a highly efficient criminal." In "The Abbey Grange" and "The Second Stain" he helps the culprits get away. No single one of these is perhaps much of a stretch beyond the Holmes we've previously had, particularly given the circumstances in each case, but the impression of them altogether is of a Holmes who operates less as a consultant to the police and more as an independent agent not wholly confined to the law.
Favorite Passage: From "The Priory School":
Holmes opened the case, and moistening his finger he passed it along the shoe. A thin film of recent mud was left upon his skin.
“Thank you,” said he, as he replaced the glass. “It is the second most interesting object that I have seen in the North.”
“And the first?”
Holmes folded up his check and placed it carefully in his notebook. “I am a poor man,” said he, as he patted it affectionately, and thrust it into the depths of his inner pocket.