The Vampire Diaries doesn't really start until 8:58 p.m.

I've said it before, but it bears repeating after this stunner. The show's propensity for shocking twists in the final moments is something fans know well, but this week's concluding sequence probably left even more jaws on the floor than usual.

What had been a slow-building, somewhat melodramatic episode suddenly changed course with not one, but two huge developments heading into next week.

Klaus turned Jenna? Did anyone out there see that coming? That was wild enough, but hearing that Damon is "as good as dead" left me at a loss for words.

This isn't to say the episode was boring prior to 8:58. Coming into "The Last Day," I assumed the title ominously referred to the final day before Klaus' big sacrifice.

It did, but it also referred, potentially, to Elena's last day as a human.

First we learn that after sacrificing a witch, werewolf and a vampire, the final step of Klaus breaking the curse is to drink the doppelganger's blood until her demise.

The imagery of this happening to Elena, combined with Joseph Morgan's tremendously creepy performance as Klaus leave no doubt how serious this is. But Elijah has a plan.

Well, he had one. Damon wasn't buying the "witch's elixir" BS. Maybe he should lay off the scotch for breakfast, because he made his most reckless move to date ...

Damon forced Elena to drink his blood so that she'll become a vampire if she dies! Many fans have theorized that Elena would turn at some point, but this quickly?

While Stefan taking Elena on that hike felt cheesy and Twilight-esque, they had to discuss the elephant in the room eventually, and now Damon forced it on them.

Unlike Bella Swan, Elena doesn't want to be a vampire. Bless her heart and the writers. This is true to her character and presents a new, complex moral dilemma.

If Elena does die and come back as a supernatural being, should we be happy? Is she going to wish she were dead? Will she never forgive Damon for doing this?

We may or may not find out soon. After a tearful kiss goodbye with Stefan that left Stelena worshippers everywhere reaching for the tissues, she vanished with Klaus.

Meanwhile, Tyler, Caroline, Alaric and Matt all played key roles last night, some more predictably than others, beginning when Maddox flung Carol Lockwood down the stairs.

Tyler therefore returns to Mystic Falls to check on his hospitalized mom, and bumps into Caroline! Lo and behold, Klaus' sacrificial cuties coming together in one location!

Maddox nabs them both, but Damon, who's already regretting what he did, is now frantically trying to postpone the sacrifice any way he can. Plan A? Get rid of the wolf.

After gathering intel from Kat, Damon heads off to find Tyler, but is stopped by Maddox, who is shot dead by ... Matt! We might make a solid character out of this kid yet!

Matt was packing heat with wooden bullets, making you wonder what would have gone down had he gotten to the tomb first or found only Damon there and not Maddox.

After they all escape the tomb, the full moon begins to rise over the horizon. Tyler can't hold off the transition, so Caroline and Matt take shelter in the Lockwood cellar.

That was a close one, but everyone's safe ... except Klaus wasn't about to be played so easily. You learn a thing or two when you've been planning this for a millennium.

Once again, Klaus proves how hard core he is by revealing - in his slow, all-knowing, sinister tone - a backup plan. One that isn't any less consequential for our crew:

1. Maddox is dead, but he can use Greta.
2. Tyler is gone, but he's captured Jules.
3. Caroline is safe, but he's got ... "her."

Her. I was wracking my brain trying to think of who it could be, but never in a million years guessed we'd see Klaus MAKE a new vampire ... out of Elena's aunt Jenna.

What I assumed Klaus would do, or try to do, would be sacrifice Damon instead of Caroline, especially after he brazenly confronted him. But Klaus has no use for him.

Katherine, his conduit, tells Damon he's as good as dead. As the screen fades to black, we see that before he escaped Tyler, he was bitten by the werewolf in transition.

Another incredible twist there. While there's no way the show is killing off Damon, I have no idea how they're going to worm out of this one. It's unprecedented.

Klaus had his Plan B. It's up to the Salvatores to come up with one now.

A final word, if I may, before turning the discussion over to your comments: I can't say enough about Ian Somerhalder as the increasingly tormented, erratic Damon.

From his sarcastic delivery ("Klaus, I presume?") to his body language and piercing stare that tell us more than dialogue ever can, he's outstanding every week.

Overall, "The Last Day" wasn't my favorite episode, but it was still very strong, heavy on emotion with more than enough supernatural action balancing it out.

Pretty much why we watch TVD, right?

With just two more episodes remaining this spring, things are certainly falling into place for a truly epic conclusion. What that entails, however, is anyone's guess.

If The Vampire Diaries has taught us anything, it's that the game and its rules change by the minute. We'll be on the edge of our seats watching right along with you.

What did you think of "The Last Day"? Discuss!

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