4: Disturbing Behavior - Episode

The title primarily refers to the fourth episode of The Vampire Diaries ' third season (and the series' 48th episode overall). Originally aired on October 6, 2011, it was directed by Wendey Stanzler and written by Brian Young. Plot Overview

: Stefan remains in Chicago with Klaus and Rebekah. While Rebekah struggles to adjust to modern fashion and music, Klaus enlists the witch Gloria to find Rebekah's missing necklace. Episode 4: Disturbing Behavior

: Gloria discovers through a vision that Elena is the one wearing the necklace. She realizes Elena—the doppelgänger Klaus needs—is still alive, but before she can tell Klaus, Katherine kills her to protect the secret. The title primarily refers to the fourth episode