Elena, Damon, and Alaric have been tracking Klaus throughout the summer, while hoping Stefan is with him, as the alternative means that he is dead. Stefan has been on a killing spree with Klaus to search for the oldest werewolf pack to create a hybrid army. Caroline throws Elena an 18th birthday party and struggles to contain her obvious feelings for Tyler.

Jeremy, alone as Bonnie is visiting relatives, has trouble dealing with the erratic appearances of Vicki and Anna’s ghosts. Damon has been the one to investigate all leads and Elena is left in the dark. She reveals to Caroline and Tyler that she had only kissed Damon to say goodbye because he was dying. After Damon and Alaric, without Elena, go to the house of Stefan and Klaus’ newest victims, Klaus is notified of Damon’s continued pursuit of Stefan and decides to do something about it.

Stefan convinces Klaus to let him go deal with it. Stefan returns to town and gives Damon a message: he wants the group to stop trying to find him and let him go. To emphasize his point, Stefan kills Damon’s compelled girlfriend Andie, while restraining a distraught Damon. Elena is angered when she discovers Damon’s closet is full of articles and notations that track Klaus’ victims. She had been going to Damon with new leads all summer and he had been the one to investigate them, but he had not told her they were on the right track.

When Elena asks Damon why he had kept his findings from her, she is disbelieving when Damon reveals that the trail of bodies are in fact Stefan’s victims. Matt is jealous of Caroline and Tyler’s growing friendship and avoids them while Alaric moves out of Elena’s house to get over Jenna’s death. Stefan returns to Klaus as promised after dealing with Damon. Klaus tells Stefan that he’ll eventually stop caring for his old life as he drinks more blood and loses his humanity.

Stefan is torn up by Klaus’ words and Elena receives an unknown call from him at the end of her birthday party. As the person on the other end remains silent, Elena realizes it’s Stefan. She tells him that she loves him and that he should never let go of that. Stefan doesn’t reply, but tearfully nods. After spending the night with Tyler in the Lockwood’s house, Caroline tries to sneak out of the house, but Mrs. Lockwood appears.

As Caroline is about to leave, she grabs her purse which has actually been laced with vervain. Caroline pulls back her hand, which confirms Mrs Lockwood’s suspicions. She shoots Caroline in the back with three vervain darts.

“The Birthday” is the first episode of season 3 of The Vampire Diaries and the 45th episode overall. It first broadcast September 15, 2011 on The CW Network.

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