Here's a word that we love to use at Shmoop when we're talking about the ends of things: the dénouement, the moment in a story when all of the plot's loose ends are resolved and all mysteries are explained. The word comes from a French verb dénouer, "to untie." This type of plot development probably reaches its height in the classic mystery novel, which is all about (obviously) untangling what is unknown.
So, it's probably not a shock to many of you that detective stories usually end with, you know, the solution to a mystery. That's part of the pleasure of reading them in the first place. But something that's kind of interesting about Conan Doyle's endings is that the solution is not always accompanied by legal punishment. Like, a satisfying conclusion to a Bones episode would be an arrest, right? And Law and Order and its many, many spinoffs are all about convicting the criminals they track down.
Holmes, though, is a private detective above all. He works for money, sure, but he loves taking clients for the interest of the case: it's the intellectual draw, rather than the financial, that really gets him. So Holmes ends up operating very much outside the law – consider the fact that he lets the jewel thief go at the end of "The Blue Carbuncle" because he honestly believes that the guy has been scared straight and won't steal again.
Because Holmes is not part of an official police force (as opposed to his much-despised colleague Inspector Lestrade), he gets some choice in how things are handled once he's solved a case. He's more interested in fairness than in observing bureaucratic technicalities.
We see examples of this interest in justice rather than in legal punishment throughout the twelve adventures in this collection, most of which never end in any kind of official police involvement. Holmes's sympathies are clearly with the high-spirited, intelligent, and ultimately honorable blackmailer, Irene Adler, over her dim-witted and coarse "victim," the King of Bohemia, in "A Scandal in Bohemia." Mary Sutherland's stepfather cannot be prosecuted for posing as her fiancé to exploit her for financial reasons, but Holmes promises "that fellow will rise from crime to crime until he does something very bad and ends on a gallows" (Identity.129). And how about the poetic justice of Dr. Grimesby Roylott's death in "The Speckled Band"? Having trained a horribly poisonous snake to come and go at his call, the snake finally turns on its master. Roylott dies the same way that he murdered one of his two stepdaughters.
Indeed, of the twelve adventures in this collection, only one, "The Red-Headed League," actually ends with a culprit getting arrested. Why do eleven out of the twelve stories avoid courts of law? We can't say there's only one answer. Certainly, keeping Holmes's cases out of court introduces a degree of unpredictability to the whole thing. Much as we enjoy a series like CSI, the formula is so strict that it does feel a little like: Crime scene. Forensics. Wrong perp first. Right perp second. Arrest. Lather. Rinse. Repeat. But Holmes is pretty nuts in his own way, and who knows what he might do? He doesn't have any outside forces (besides nature and chance) telling him what to do.
We all know the basic rules of human society and Holmes breaks plenty of those during his mystery-solving adventures. But Holmes's position outside the police system makes it possible for him to think through moral problems that might be too small for a real legal case, such as the lies Neville St. Clair tells in "The Man with the Twisted Lip." It also allows Holmes to consider larger morality outside of public institutions, as in his sympathetic decision to allow Charles McCarthy to live out the few months of his life at home instead of in jail after he commits a much-provoked murder.
And, honestly, even beyond whatever lessons Conan Doyle might be trying to teach about the Golden Rule or about divine punishment (because what else can we call that shipwreck that kills murderous Klansman James Calhoun in "The Five Orange Pips"?), it's really comforting to read stories that are about making the world just. As our parents have told us time and time again, life isn't fair. But, by the end of a good Holmes story, you feel like it can be. The good are rewarded, the bad punished (shipwrecks, dogs, and Indian swamp adders, oh my!), and each man gets what he deserves. We wish real life ended Holmes's way.