Killers are on the loose when "The Vampire Diaries" returns for its eighth and final season.

The extended trailer for season 8 showed that Damon (Ian Somerhalder) and Enzo (Michael Malarkey) will still be under the control of the monster in the vault. The pair will be on a spree to victimize people by kidnapping them and hanging them from the ceiling.

One of the significant kills is nanny Seline (Kristen Gutoskie), who seemed to be attacked from behind by someone who slit her throat.

But Damon's brother, Stefan (Paul Wesley), and Bonnie (Kat Graham) will not give up until they rescue the two. In the trailer, Bonnie lamented that the search for the men seems never ending. But according to Stefan, "We have to follow every single clue like it's the one that's gonna lead us to them." Bonnie agreed since she knows that they need to find the two in order to rid them of the evil monster who possess them.

The trailer also revealed that Stefan will finally catch up with Damon, but his elder brother was busy dropping a man into a container filled with water. He will try to talk some sense to the elder Salvatore, but Damon will tell him that "Once the devil comes a calling, you're done."

Meanwhile, talks about Nina Dobrev's return in the series as Damon's one great love, Elena Gilbert, continues. Dobrev left the series at the end of season 6, and her character was placed in a prolonged sleep because of Kai's (Chris Wood) spell. But according to reports, the actress will once again reprise her role to say her final goodbye to the fans in the final season of "The Vampire Diaries."

However, the actress and the show's producers are still mum about the plans for Elena's return to Mystic Falls.

"The Vampire Diaries" season 8 premieres on The CW on Friday, Oct. 21.