Kayla Ewell Kayla Ewell

Vicki and Anna may have been together in their shocking return to Vampire Diaries, but when the show returns for Season 3, they'll be anything but united.

"Vicki has a master plan and it's trying to be stopped by Anna," Kayla Ewell, who plays Vicki Donovan, tells TVGuide.com. "A lot of what Anna says is, 'Beware of Vicki, be careful.'"

Is The Vampire Diaries on your Watchlist? Add it and your other favorites now and never miss an episode

Besides being dead vampires, Vicki and Anna (Malese Jow) have another thing in common: Jeremy (Steven R. McQueen). When the show debuted, Vicki and Jeremy began hooking up and developed deep feelings for each other — until Vicki was turned and killed. Anna soon came to town and she and Jeremy got together. He even asked her to turn him, but she met her demise in the finale. Vicki and Anna came back as ghosts in the final moments of Season 2, and Ewell says the two will be definitely around for a significant chunk of episodes in Season 3.

With both Vicki and Anna back, a battle is in the offing. "They keep hinting towards this huge epic fight between Bonnie, Anna and Vicki," the 25-year-old actress says. "If that were to happen, there would be major powers at stake there because we're talking two vampire ghosts and a witch."

Vampire Diaries Season 3 preview: Will Jeremy see more dead people?

That witch just happens to be Jeremy's girlfriend — meaning Bonnie and Jeremy's blissful romance will hit some bumps because of Vicki. "All Vicki does is toy with people. She doesn't know any other way," Ewell says. "Of course I think ultimately Vicki wants Jeremy to be happy ... but Vicki she can be selfish and her one and only love is Jeremy so she's going to go for it as much as she can. Vicki's trying pretty hard to get back into his life and I think there will be a lot of success there."

Along with Vicki's determination to get back into Jeremy's life, she has another mission in returning to Mystic Falls: to reconnect with brother Matt (Zach Roerig). "She died and Matt never really got any answers as to why and how. They're really addressing a lot of that and our past," she says. But if Vicki's a vampire-turned-ghost and Matt's a human, how will the two communicate? Ewell explains that, for now, Vicki will try to let Matt know she's "alive" by moving things around the house, but adds, "I do say I can come back...they've been teasing we don't just remain ghosts."

And Ewell says the returning Vicki is amped up, explaining: "Vicki got screwed out of life, so she's back for redemption."

The Vampire Diaries returns Thursday, Sept. 15 at 8/7c on CW.

Follow @RobynRossTVG for more scoop on The Vampire Diaries.