Spoiler From EW - 7th September 2012

What to expect this season: The Salvatore Brothers (Somerhalder's Damon and Wesley's Stefan) will disagree over whether ultra sensitive new vampire Elena (Dobrev) could handle hurting a human, but come episode 2, they'll have an additional worry: the arrival of a vampire hunter (Todd Williams) with an enigmatic origin story that piques the interest of Klaus (Joseph Morgan) and figures into the larger mythology for season 4. After deciding to hang around Mystic Falls while he investigates the mysterious vampire hunter, Klaus will also commit himself to his crush on Caroline (Candice Accola) for the long haul and ponder fun ways to screw up her relationship with Tyler. One will involve guest star Phoebe Tonkin (The Secret Circle), who'll recur as a friend of Tyler's (Michael Trevino) named Hayley. 


Plec says: ''All we know about Hayley thus far is that she shows up in the third episode and it's clear that she and Tyler have a history that we weren't aware of, that Caroline isn't aware of, and that Klaus learns of very quickly. So in the spirit of (how can I drive a wedge between Tyler and Caroline?), Klaus gets to have a little bit of fun with the existence of this girl.''