Plot summary
Caroline has become a vampire and awakens in the hospital craving blood. Tyler catches Mason searching for a moonstone, which is a family heirloom. At the carnival, Damon compels a boy named Carter to pick a fight with Tyler to provoke one of Tyler's bursts of anger. Mason breaks up the fight using his supernatural abilities, proving that he is a werewolf. Caroline confronts Damon about his abusive treatment, and he realizes that she is a vampire. He alerts Elena and Stefan, while a ravenous Caroline drains Carter. Stefan promises Caroline he will guide her journey as a vampire. Tyler retrieves the moonstone Mason has been seeking. Matt notices Caroline's erratic behavior but admits that he loves her.
Credits
Adapted from Wikipedia contributors, The Vampire Diaries season 2. HTML formatting and reference markers removed.