This. This is The Vampire Diaries firing on all cylinders.
Last week’s 100th episode was a lot of fun, but it showed obvious strain in an attempt to properly commemorate the momentous occasion while still telling a compelling TVD story. “The Devil Inside,” free from these shackles, practically explodes onto the screen with unfettered glee and doesn’t let up until the very end. It’s a good time, but more importantly it’s a good story told well, and that’s something that has been sorely missing for a lot of this season.
The reason this whole thing works so well is that the show finally has a compelling antagonist again. The first stretch of season five was sorely lacking a charismatic, complex central bad guy, and the show suffered as a result. Katherine is not only a fabulous antagonist, but she’s a richly complicated, interesting character with centuries of shared history with the Salvatores and a wicked sense of humor to boot. Bad guys are always more interesting when it’s easy to root for them to succeed, either secretly or not so secretly, and it is shockingly easy to root for Katherine. None of this would work, though, without Nina Dobrev’s fantastic performance. Her ability to switch between Katherine and Elena by simply giving a sideways look is a remarkable bit of acting, but beyond the little moments like this it’s Dobrev’s commitment to Katherine’s resilience that shines through. Katherine defines herself as a survivor and you can feel that personality trait in every fiber or Dobrev’s performance, even down to the way Katherine steels herself to deal with the more annoying aspects of life as pretending to be Elena Gilbert. Dobrev has been the show’s not-so-secret weapon for most of its run, so it’s always exciting to see her get to stretch her acting muscles so thoroughly.
Story-wise, Katherine fully taking over Elena’s body and then deciding to stay in Mystic Falls and attempt to win Stefan back is so devilishly clever that it seems surprising it took so long for the show to get to it. TVD is a show built on a love triangle, and for the last three seasons it has practically beaten the triangle to death playing a lot of the same beats over and over again. With this story, the show gets to exploit the angles of the triangle from a completely new perspective while still torturing all of the various legs of the triangle in the process. Katherine pretending to be Elena and trying to win Stefan over has so many possibilities for hilarity and heartbreak, which is exactly what Katherine as a character should bring: A constant stream of broken hearts and broken dreams as she barrels through life, going after whatever she wants, whenever she wants.
Katherine’s first casualty came immediately, as she absolutely destroyed Damon the very second she took over Elena’s body. Damon’s pure vitriol against Katherine felt maybe a bit over-the-top in the last two episodes, even for Damon, but it’s obvious now it was all leading up to this moment where Katherine could exact her revenge and metaphorically rip out Damon’s heart and stomp on it (right before turning away with a smile, naturally). That Damon immediately turns to his dark side to alleviate his pain is completely, totally Damon. That he does it by murdering one of Elena’s friends is surely going to come back to haunt him. And that he teams up with the still-mysterious Enzo and pulls the road trick to do it, well, that’s just fun for the audience.
The biggest question hanging over last week’s episode for me, though, was what the show was going to do about Caroline’s hookup with Klaus. Instead of sweeping it under the rug (which was my fear), the show deals with it rather marvelously here, having Tyler find out about it and rightfully lose his mind on Caroline. What’s great about the whole situation is that Tyler’s anger is totally understandable, as was Caroline sleeping with Klaus, as is both of their reactions to the news coming out. It’s also the show actually confronting the fact that many of the people they associate with are horrible mass murderers and what that means, if only for the briefest second. That it wrapped up with Stefan making Caroline feel better for doing something impulsive, showing her compassion as she showed him with the Katherine situation, is a lovely way to illustrate that things in this world are rarely black and white, all while reinforcing Caroline and Stefan’s bond.
It’s character moments like these, moments mixed in with all of the twisty drama and moments that have been few and far between this season, that suddenly make the show feel like it is snapping back into focus again after being in the blurry dark for far too long. With Katherine Pierce as our guide, how could we possibly get lost again?
Stray observations:

• Matt had more lines tonight than he’s had in two seasons. I declare 2014 the Year of Matt!

• Here’s the thing about Katherine taking over Elena: They burned her body! Elena has to eventually come back, and they burned Katherine’s body! I’m going to need a new doppelgänger body for Katherine to jump into eventually, because I refuse to believe the show will let her (and Dobrev’s performance of her) die.

• Stefan’s been pretty great lately, trying to help Damon get Elena back and talking Caroline down from her despair after her encounter with Tyler. He’s been far too even-keeled, so of course Katherine is about to completely mess with his head.

• Now that all of the Whitmores are gone, is the Augustine threat gone as well? Or should Damon and Enzo take a little trip to visit Dr. Maxfield?

• Why do all of these people show up to Matt’s party? Doesn’t anyone realize Matt and his friends have an extraordinarily high death count surrounding them?

• “No to the dress, yes to the shoes.” Matt Donovan, fashionista.

• Stefan: “I’m not giving you the pouty face. This is my ‘you’re being a dick’ face.”