The Vampire Diaries (2009)

This season, Katherine's appearance in Mystic Falls will throw a wrench into the love triangle between Stefan, Elena and Damon, and the other residents of Mystic Falls must choose sides as they fall victim to a new breed of danger. New and unexpected friendships will be forged, allies will become enemies and hearts will be broken. Plus, Stefan and Damon will be forced to face a villain more evil and diabolical than they thought possible.