Season 3 delves into the origin of the vampires: . We learn that Klaus has a family of vampire siblings—Elijah, Rebekah, and Kol—who are thousands of years old. Stefan goes on a "ripper" (out-of-control killing spree) with Klaus to save Damon from a werewolf bite, leaving Elena to fight for his soul.
A high school student grieving her parents' death who discovers she is a "doppelgänger" of the brothers' past love, Katherine Pierce. vampire diaries full series