And sometimes, Vampire Diaries still kicks your ass with greatnessVampire Diaries is usually at its best when it focuses on the core characters and their ever-shifting relationships — particularly the central love triangle. And when it finds new things to say about its core themes of power and mind-control. So probably no surprise that last night's amnesia episode was the best in ages.

Spoilers ahead...

The thing of Stefan losing his memory looked as though it was going to be ridiculous — the way 99 percent of amnesia plots are, generally. But instead, it turned into a clever examination of the psychology of Stefan, as the newly tabula rasa Muppet Angel tries to figure out who he actually is.

We sort of run through the whole history of Stefan in an hour, starting with the original dynamic between him and Damon — as they joke, Stefan is the "safe brother" and Damon is the "fun brother." When Stefan tries to swap that around, Damon wrecks the car they're riding in. And soon enough, Stefan is trying to figure out his whole "Ripper" deal. And that's where things get interesting.

Originally, Stefan was the "good brother" because he didn't drink human blood — but over time, Damon proposed an alternate theory: actually Stefan just doesn't know how to indulge in moderation, so he's actually just the brother who lacks self control. Now that Stefan has amnesia, though, it's not clear whether his tendency to rip the heads off his victims will persist, or if that was a psychological condition created by Stefan's experiences.

There are a lot of "nature vs. nurture" jokes in this episode, as we try to plumb the depths of Stefan's pathology — was he a serial killer out of guilt for killing his own father and turning Damon into a vampire, actions he no longer remembers? In that case, he should be fine now. Or is it something biological, or essential to his nature?

Elena shows up and attempts to distract Stefan from killing any innocent waitpersons — basically by reminding him of their courtship, and we run through the whole Stefan/Elena relationship in about five minutes. (Gotta love how fast this show moves.) But if Stefan is no longer centered around guilt, thanks to his amnesia, then what is Elena to him? She's the one who distracts him from his bloodlust, apparently.

All of this leads to the kicker — when Stefan finds out that Elena is dating his brother Damon, he's royally pissed, more angry than he let himself be the first time around. And this leads to him going "Ripper," not out of sublimated guilt or self-loathing, but out of pure anger. It's more of a Damon move than a Stefan move — but it suggests that maybe the Ripper thing was always Stefan's suppressed anger coming out, all along. Maybe the anger is what always lay underneath Stefan's guilt.

In the end, self-loathing (and self-control) reassert themselves, and Stefan decides he's going to be a whole new person, without all his old baggage to hold him down. He even burns the titular Vampire Diaries! (Damon's line, "Did we just get dumped," is priceless.) And we end up recapitulating the most recent development in Stefan's journey — he's found that the only person he can really count on, or communicate with, is Caroline. Who's arguably the only good person on this show.

Running through all of this is an interesting question of identity, as Stefan tries to figure out whether he's a monster and why he should bother to try and be good. He's no longer motivated by any of the things that motivated him before — although he immediately has a thing for Elena — so he's reasoning from first principles instead. He's a vampire, so why shouldn’t he feed? And what debt should he owe to a past he no longer remembers?

When a show's been on the air for five years, as TVD has, then it's likely to get weighed down with all its excess continuity and years of wacky plot twists. (Who hasn't Damon murdered, at this point?) But you also get to take advantage of those years of character development and relationship-building, for an episode like this one, where all of the past serves as touchstones for reexamining the show's core dynamics.

And sometimes, Vampire Diaries still kicks your ass with greatness

And meanwhile, in the episode's main subplot, Bonnie's death is finally revealed, and this leads to a lot of freaking out (including Elena making a speech where the only nouns are "I" and "me") and a beautiful funeral scene, where Tyler randomly reappears. The best bit of the "dealing with Bonnie's death" subplot, though, is probably how Damon reacts — you think he's about to throttle Jeremy but instead he gives the Gilbert kid a really intense hug. Awww.

In other news, Matt manages to videotape the Traveler who's hijacked his body, who takes advantage of this fact to bluff Matt and to reveal that his magic knife is super-important. Matt can't call on Bonnie for help, and nobody else seems too worried about him — too bad Matt doesn't know an Original Vampire who he just spent the summer traipsing around Europe with and whose fault all of this arguably is. That really is too bad.

And also, Caroline has a really sweet date with Jesse, the hot T.A. from Professor Evilpants' Evil Biology Class. Who, this being TVD, is immediately attacked, and later turned into a vampire by Professor Evilpants. Oh well.

And sometimes, Vampire Diaries still kicks your ass with greatness

All in all, though, this was a really powerful emotional episode, where the emotion came from a deep knowledge of the characters and how they work — when these characters surprise us, even after all this time, it's because they have such a huge store of past events to draw on, not because they're acting randomly. (For the most part, anyway.)

Oh, and I'm still watching The Originals — which is still watchable, for sure. This week's episode, with its heavy-handed speechifying about the Nature of Evil, was fun and moved a lot of stuff forward. I've developed a theory about that show — I think Cami, the bartender/psychologist, was supposed to be the one normal human that we identify with, our way in to all of this vampire/witch/werewolf melodrama. But for whatever reason, the writers changed their minds and Cami just became another pawn on the board. Probably a good thing she's suddenly got her own supernatural backstory and a reason to want revenge on whoever compelled her brother to go spla, then.