The Lost Vampire

The season begins after the deaths of Elena and Jeremy Gilbert's parents. Both are put in their Aunt Jenna's custody. Jeremy has become a loner and Elena starts dating a boy named Stefan Salvatore. It is soon revealed that Stefan is a vampire and his brother Damon shows up in Mystic Falls and kills people at random.

Another supernatural revelation occurs when Elena's friend Bonnie Bennett discovers she is born into a line of witches and is a witch herself. She gets help from her grandmother to use her powers. Elena's friends and acquaintances also become involved such as Tyler Lockwood, son of the mayor, and Matt Donovan, Elena's ex-boyfriend and Caroline Forbes, daughter of the sheriff. It also turns out that Elena is the doppelganger of Katherine Pierce, a woman who, centuries ago, seduced the Salvatore brothers and turned them into vampires, turning their vampire hunting father against them, though Stefan ends up killing him. Katherine was presumably trapped in a tomb beneath the church and Damon is planning on releasing her. Lexi, a friend of Stefan's shows up and befriends Elena, but is killed by Damon, driving a wedge between brothers.

Jeremy falls in love with Vicki Donovan, Matt's sister, who uses drugs like him, but she was dating Tyler and starts a rivalry between the boys. Vicki breaks up with Tyler for Jeremy. She is later turned into a vampire by Damon, but her bloodlust was out of control and she is killed by Stefan. Jeremy witnesses this and Elena asks Damon to make Jeremy forget this to spare him the pain. Matt on the other hand is devastated.

After the history teacher is killed, a man named Alaric is hired to take his place. Alaric came to town to kill Damon, believing him to have killed his wife, Isobel. Damon tries to kill him in self-defense, but Alaric wears a ring that keeps him from dying at supernatural hands. It is revealed Damon didn't kill Isobel, but turned her into a vampire on her own account. Later, Alaric and Damon become friends.