S5, E21: When Stefan and Elena escape from Markos' (recurring guest star RAFFI BARSOUMIAN) control, only to find themselves stranded in a remote location, Stefan gets philosophical with Elena about her relationship with Damon. After their attempt to protect the doppelgangers goes badly, Liv (recurring guest star PENELOPE MITCHELL) and Luke (recurring guest star CHRIS BROCHU) come up with a dangerous new strategy. Damon recruits Matt and Jeremy to help him set a trap for Markos, who turns out to have a devastating surprise of his own. Bonnie finally admits to Caroline that she's been keeping the truth about the Other Side from everyone. Finally, while Bonnie searches desperately for a way to stop Markos, Caroline is witness to an unthinkable act of violence by one of the Travelers.