<P> The Vampire Diaries , a 40 minute American supernatural drama , was officially renewed by The CW for a full 22 - episode season on February 16 , 2010 . The first episode premiered on September 9 , 2010 , at 8 p.m. ET . The season picks up immediately after the events of the season one finale . All the series regulars returned . Season two focuses on the return of Elena Gilbert 's ( Nina Dobrev ) doppelgänger , Katherine Pierce , the introduction of werewolves , the sun and moon curse , and the arrival of the original vampires. Tyler Lockwood 's ( Michael Trevino ) uncle , Mason Lockwood ( Taylor Kinney ) , arrives in town searching for the moonstone , a family heirloom. Tyler later learns of his family 's werewolf curse . Meanwhile , Caroline Forbes ( Candice Accola ) is killed by Katherine while having Damon Salvatore 's ( Ian Somerhalder ) blood in her system , turning her into a vampire . The arrival of the original vampires , Elijah ( Daniel Gillies ) and Klaus Mikaelson ( Joseph Morgan ) , also bring about complications . Klaus is a vampire - werewolf hybrid , but his werewolf side had been forced into dormancy by witches , as nature would not stand for such an imbalance in power . Therefore , Klaus arrives in town with plans to break the curse and unleash his werewolf side by channelling the power of the full moon into the moonstone , sacrificing a vampire and a werewolf , and drinking the blood of the doppelgänger . The season is currently on air in Urdu on filmax channel in Pakistan . It became available on DVD and Blu - ray on August 30 , 2011 . </P>
when does elijah first appear in vampire diaries
Season two