After a brief hiatus, "The Vampire Diaries" will return this Thursday with an all-new episode filled with surprises.

Executive producers Caroline Dries and Julie Plec revealed that Stefan will learn that he has a relative in the upcoming episode, titled "I Alone."

"I'm Zach and Gail's daughter, Sarah Salvatore," says a young woman as she introduces herself to Stefan, who seems to be in total shock, in a preview video.

In response, Enzo will be very intrigued and search to get to the bottom of this mystery.

Meanwhile, Damon and Elena will figure out a way to help Bonnie escape her time prison by traveling to the prison world and then bringing her back home with them.

However, Plec confirmed that Kai has escaped from the prison world and is setting out to merge with his sister, Jo, and then take control of the Gemini Coven.

The CW also released a sneak peak video of Elena telling Jeremy that Bonnie is still alive. In the video, the siblings are seen taking a jog around Whitmore College. Jeremy says that after grieving the loss of his girlfriend and struggling with alcoholism, he is finally ready to move on. That's when Elena turns to him and begins talking about Bonnie.

According to Plec, fans should not hold their breath waiting for Damon and Elena to get back together in the Christmas-themed midseason finale.

"There is mistletoe in the midseason finale, and fans are free to wish for anything they want - and also prepare for crushing disappointment in the way that we always tend to like to serve it to them," said the EP, according to TV Line.

"The Vampire Diaries" also released a synopsis for "I Alone," reports Dread Central, which states:

"Damon (Ian Somerhalder) finds himself in hot water after he carries out a plan that requires Alaric's (Matt Davis) unwilling participation.

"When Elena (Nina Dobrev) shares some hopeful news with Jeremy (Steven R. McQueen) about Bonnie (Kat Graham), she is caught off guard by his reaction. Liv (guest star Penelope Mitchell) helps Damon and Elena with their plan to get Bonnie back, but when things take an unexpected turn, she's left with a difficult choice to make.

"Elsewhere, Matt (Zach Roerig) takes matters into his own hands when Enzo's (Michael Malarkey) actions cross the line, and Kai's (guest star Chris Wood) existence continues to be a dangerous threat."

"I Alone" will air on "The Vampire Diaries" on Thursday, Dec. 4 at 8 p.m. ET on The CW.

Watch preview videos below.