After two decent episodes that featured momentary delights, if not all-engrossing plots like seasons before, Sherlock ends on one of its strongest episodes ever. Objectively, “His Last Vow” ranks behind only “The Reichenbach Fall”, but personally I’d put it ahead of “Fall” simply because “Fall” kind of hurts to watch and “Vow” doesn’t, which makes it a little more re-watchable, but that’s just me and my angst-avoidance policy. Still, “Vow” is a tremendous episode that features the best acting yet from Martin Freeman and Benedict Cumberbatch, as well as a satisfying arc for Amanda Abbington as Mary Watson, and Danish actor Lars Mikkelsen (brother of Mads) turns in a brilliantly creepy performance as the villain, Charles Magnussen. Overall, it’s a stellar episode to close out Sherlock’s third season.
The title refers to the toast that Sherlock made at John and Mary’s wedding in the previous episode. Obviously we’ve already seen Sherlock go to extraordinary lengths to protect John, but in this episode he goes even further, doing just about the most extreme thing a person can do to ensure someone’s safety—commit murder. But first we have to deal with the circumstances that push Sherlock Holmes so far into a corner that he has no other options.
The episode opens a month after the wedding and John, itching to see some action, goes looking for a drugged-out neighbor in a smack house. There he also finds Sherlock, apparently fallen off the wagon. John is understandably furious but the scene standout is Louise Brealy as Molly Hooper, the one who takes Sherlock to task for “throwing away” his gifts. There’s clearly been some effort this season to make Molly less of a walking punchline and it is much appreciated. She comes across as a fuller person, and one who has grown and changes in the years she has known Sherlock. Watch her first scene in the pilot and then watch her slap Sherlock and enjoy how far she has come.
The reason for Sherlock’s binge is case-related (and he keeps saying that like it’s supposed to make drug use okay, and then gets confused when everyone else doesn’t get it). He’s trying to get on the radar of Charles Augustus Magnussen, a newspaper owner and intensely creepy blackmailer. Mikkelsen plays Magnussen with lizardly smarm and is, in my opinion, the vilest and most frightening of Sherlock’s enemies. Moriarty was a psychopath and unpredictable, but ultimately Sherlock had his number all along. Granted, Sherlock had to go to tremendous effort to best him, but Moriarty was best-able. Magnussen, however, is not. He’s cold, calculating, unemotional, and just as smart—if not smarter—than Sherlock. He also has zero regard for people’s personal space.
And Sherlock plays right into his hands. With the advantage of hindsight we now that it was Moriarty dancing to Sherlock’s tune all along, but in “Vow” I think we see Sherlock truly beaten for the first time. His best educated guess was wrong, and Magnussen ends up gloating in his victory over Sherlock, John and Mary. The only possible out for Sherlock is to kill Magnussen, which shocks everyone, but Sherlock did promise to do whatever he could to make sure that John, and by extension Mary, are safe. Mycroft looks truly horrified by what Sherlock’s done (and the intercutting between grown Sherlock and the child Sherlock—as Mycroft sees him—as Sherlock surrenders to police could have been corny but plays beautifully), but it’s the only logical conclusion to the problem of Magnussen blackmailing the Watsons forever.
The surprise reveal of Mary’s shady past was a solid bit of plotting. It gives her real depth as a character, and introduces, for future seasons, the prospect of Mary working with Sherlock. It also provided fodder for a great scene between John and Mary that both Freeman and Abbington absolutely crushed. Abbington also crushed it in Mary’s confrontational scene with Sherlock—at points this season the acting has tended toward hammy as everyone played to the audience (that smuggy tone that plagued the first episode), but “Vow” avoids that completely, going for restraint more often than not. Even the stylized editing is on a shorter leash, really only emerging as Sherlock tries to out-think his own death (GREAT sequence, by the way).
“His Last Vow” is a terrific episode, highlighting everything there is to love about Sherlock. It’s fast-paced, offers a complex and interesting mystery, provides strong character beats for all the major players and yet still retains the sharp sense of humor that colored the first season. It also ends on a cliffhanger (though one not nearly as obsessing as “Fall’s”) as Moriarty appears to come back from the dead. We know, of course, that he is really quite dead, so who could it be, pulling the strings? Jeannine, Sherlock’s sexy Irish ex? The still-unseen Sebastian Moran? Or some other criminal Sherlock managed to piss off? We’ll have plenty of time to speculate.