If you think you’re going to get Nina Dobrev to tell you who Elena chooses — Stefan (Paul Wesley) or Damon (Ian Somerhalder) — in tonight’s season finale of The Vampire Diaries, think again: She hasn’t even told her mother. “She lives between Canada and Europe, so I don’t get to see my mom very much. Her way to kind of be with me is watching the show and Googling me wherever I am,” Dobrev says, with a laugh. “So on many occasions, she calls and asks for spoilers and I’ll always say, ‘Nope! Nope! I’m not telling you anything.’ She always gets a little bit upset at the time, but then ultimately, she’s happy that I didn’t ruin it for her. It’s like the way I don’t want to know what happens in an episode before I read it. You don’t want to get to the punch line before you hear the joke.”

Of course, the Vampire Diaries season finales, while sure to have some nice one-liners, aren’t typically remembered for their guffaws. It’s more like murder, mayhem, and tears (which is exactly what EP Julie Plec told us to expect this year). Season 3?s twist-filled final hour will be gut wrenching, Dobrev says. ”Especially at the end, there’s a huge twist that even we didn’t expect when we were reading it. And it actually changed. We started shooting the episode, and they changed it before we shot [the ending] to something completely different,” she says. “It’s sad. When I was watching parts of it in ADR the other day, I almost started crying. The people who are loyal fans and live and breathe with the characters are gonna really feel it at the end of this episode.”

As those devoted viewers know, Klaus (Joseph Morgan) — who insists he’s at the start of our heroes’ vampire bloodline, which means they can’t kill him or they, too, will die — is now lying desiccated in a coffin on his way to being dropped into the Atlantic Ocean by the Salvatore Brothers. Klaus had tried to drain Elena of all her blood, which he needs to make his hybrid army, because if she dies, otherwise immortal Alaric (Matt Davis) will die, too. Everyone wants Alaric dead now that he’s determined to stake all four remaining Originals so all vampires will die. We also know from the promo that at least two of Klaus’ three remaining siblings, Rebekah (Claire Holt) and Elijah (Daniel Gillies), are back in town. “The whole season up until this point, it’s been the Originals versus the regular vampires and the humans. And now it’s all coming to a head. Somebody — if not multiple people — has to die in order to save others.

It’s a war to survive,” Dobrev says. “Elijah represents the Originals and he’s gonna try to make sure none of the Originals die, whereas the humans are trying to make sure the vampires they’ve befriended and grown to love don’t die. So everyone’s just trying to look out for themselves and continue the bloodline.” That could explain why the hospital — where we’ll find Elena after she hit her head during last week’s Klaus scuffle and later fell unconscious — won’t be the safest place for her. Presumably, the Originals will want her dead, and Alaric will want to keep her with him so he can keep her alive (until he needs to kill her to commit suicide, of course). One Salvatore brother will have to return immediately to protect her, and the other will continue with Operation Dump Klaus, which apparently doesn’t go according to plan since we’ve seen a clip of Damon taking Bonnie to Klaus’ coffin in a storage facility.

While we debate what’s going to happen in the present, we’ll also get to learn more about the past through flashbacks to Elena’s life before the Wickery Bridge car accident that killed her parents and Stefan saved her from drowning. Dobrev won’t say whether we’ll actually see Stefan’s rescue, but she offers this about those flashbacks, which feature Aunt Jenna (Sara Canning) as well as Elena’s parents, Grayson (Jason MacDonald) and Miranda Gilbert (Erin Beute): “They really show you the relationship they had, and it makes the end of the episode and the whole car accident so much more tragic, and visceral, and sad,” she says. “When you see the back story, you see how happy they were. You see how much her life has changed, and how so much can change in one second.” She also says that’s the same cheerleading outfit she wore in season 1: “But it’s funny, it definitely didn’t fit the same two years later,” she adds, laughing, “and I didn’t feel as secure in it. Two years ago, I felt like such a baby, and just like my character, I feel like I’ve become more of a woman, and I’ve filled out in places where I wasn’t endowed before.”

“The whole theme of the episode is about time and change, and making decisions and letting go based on the maturity that you gain from experiences good or bad,” Dobrev says. So yes, it all comes back to Elena’s decision. “As we approach the end of the episode,” Plec says, “we’ll put Elena in that situation where there’s only one brother that she can see in a very important moment, and she needs to decide which one of those brothers it is.” How does Dobrev think the show’s notoriously passionate and vocal fans will react? “I think half of them are sitting at the edge of their seats hoping and praying that she’ll choose Stefan, and the other half is doing the same for Damon. But I think that ultimately, they’re going to respect her decision and understand where she’s coming from and why she makes it.”