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The key word is "Enzo". Preview to the 13th episode of "The Vampire Diaries" season 5 reveals Damon and his former Augustine cellmate Enzo, played by guest star Michael Malarkey, making a pact against Stefan's pleasure.

After making a disturbing discovery, Stefan has a frustrating conversation with Damon and Enzo. Still bent on revenge, Damon and Enzo resort to violence to convince Bonnie and Jeremy to help them, but their plan takes an unexpected and horrifying turn.

Also in the episode titled "Total Eclipse of the Heart", hoping to help everyone move past recent traumatic events, Caroline convinces Elena and Bonnie to attend Whitmore College's "Bitter Ball" for broken-hearted students. Bonnie is intrigued with a fellow student named Liv, who appears to be dabbling in witchcraft. Tyler starts to worry about Matt's relationship with Nadia. Dr. Wes struggles to continue his research project with help from a new benefactor named Sloan.

Australian actress Penelope Mitchell and "I Am Legend" star Caitlin McHugh are guest starring as the new characters, Liv and Sloan, respectively. The episode airs February 6 at 8 P.M. ET on The CW.