After a break that felt like an eternity, even by the standards of our favorite undead characters, The Vampire Diaries returned in vintage fashion Thursday night.

"Know Thy Enemy" showcased all that we love about TVD: Deception, betrayal, shocking twists, things you didn't even know were possible and Damon shirtless.

One of my frequent issues with the show is that there's almost too much going on. This seemed true at the onset last night, but things blended together perfectly.

Let's break down the major storylines, where we stand and what's next:

Isobel returns, lies a lot and eventually dies! Man, does it get any harder to figure out what's really going on than when Isobel, John and Katherine are ALL plotting?

Elena's biological parents (something that's still hard to wrap your head around) say that all of their actions were geared toward making sure Klaus didn't know about her.

Sounds almost sweet. BUT, Isobel then reveals to Katherine that she made a deal with Klaus to keep her safe if they give him the doppelganger and the moonstone. Gulp.

Katherine stumbles upon that very gem in the worst hiding place ever (we'll forgive this only for the ensuing Damon scene), building the suspense for the double-cross.

Or should I say double-double-cross?

Isobel has a giant witch dude kidnap Alaric, then temporarily "kills" John - I loved Damon's nonchalant reaction - in a plan orchestrated so Katherine can kidnap Elena.

THEN, naturally, she calls Katherine and drops the hammer. She was playing Kat too. The giant witch appears to abduct Katherine, while Elena is saved by her mom.

Of course, Klaus is the true puppet master in all of this, having compelled her the entire time, but Isobel follows it up with her first-ever act of selflessness ... or was it?

It's unclear if Klaus also prompted her shocking demise, but in any event, she tore off her necklace and let the sun incinerate her, fittingly standing over her own grave.

One death down, two to go.

I thought this was a great way to end Isobel's role in the saga. She redeemed herself (somewhat, maybe) while boosting John's status in Elena's mind as well.

To think, he was actually the good guy in all of this. Only compared to two huge blood-sucking liars, sure, but hey. Can Elena really trust him going forward, though?

Another interesting development in the aftermath: Damon and Stefan signing the Salvatore house over to Elena. Why do I not think that's an airtight plan?

Bonnie can kill an original, but it'll kill her too! Upon finding the ancient burial ground, Bonnie harnesses her predecessors' power so that she may one day off Klaus.

The only caveat? If she uses too much witch power at once, she herself will die. Obviously, taking down the oldest vampire in the history of time will require every last bit.

This is a great development, as it sets the stage for Bonnie making the ultimate sacrifice for others, as Elena as already vowed to do. She seems hell bent on doing so, too.

It would also make sense that Klaus' death, if that occurs, comes at a heavy personal cost for the show's core characters. On a side note, how cute are she and Jeremy?!

Matt sold out Caroline! I absolutely love this twist, because Matt just got really interesting. Guess what Caroline revealed in the previous episode was simply too much.

I still never expected he had this in him though. After making Caroline tell him everything, playing on her own emotions and guilt, he asks that she compel him to forget.

Only Matt was strung out on vervain and only acted like he was compelled! He's in cahoots with Caroline's mom, and reveals all of C's secrets to the sheriff at the end.

Caroline and Matt, much as I like them, were somewhat fringe characters at times. Now they find themselves enmeshed in a plot line that could be fascinating to watch.

Oh yeah, and Klaus is in Alaric's body! The episode could have ended with Isobel's death, Bonnie's revelation and Matt's meeting with Sheriff Forbes and been great.

This is The Vampire Diaries, though, and we were thrown another jaw-dropping cliffhanger to top it all off. Like Matt, Alaric is suddenly back in the mix unexpectedly.

Unlike Matt, he doesn't know it. That's because in the closing moments, the huge witch who kidnapped Katherine is seen casting an elaborate spell on 'Ric, then kneeling.

Bowing down was a great touch. It said everything while saying nothing. Is that ... no ... it can't be! What a well-conceived way of introducing Klaus ... Klalaric ... whatever.

Klaus greeting Katherine with an entirely different voice from Alaric's body was a shockingly eerie way to end the episode and a great precursor to the coming weeks.

Alaric has to be doomed now, right? It's hard to see this ending well, given that we know Klaus will be arriving in earnest soon enough. But on TVD, you just never know.

What's Klaus' goal in possessing Alaric? Does it get him closer to Kat/Elena without exposing himself? Will this ultimately fail, thus leading to him actually showing up?

So many unanswered questions, so much to debate. All I know is that for all the confusing twists and turns "Know Thy Enemy" took, it was a great ride throughout.

What did you think of last night's Vampire Diaries? Were you expecting any or all of these developments, and what do you see happening next week? Discuss below!

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.