In season 2, the Stefan/Elena/Damon will evolve into a Stefan/Katherine/Elena/Damon quadrangle and surprisingly it will be Stefan, NOT Damon, who will be the most affected by Katherine’s return: it will turn out he’s not as over her as he thought he was. Elena will come to come to terms with the fact that she may have developped feelings that are more than friendly towards Damon. Damon, on the other hand, will be busy devising a plan with the Council of the Founding Fathers to take down Katherine.
And yes, werewolves will be introduced next season and one of them (probably Tyler?) will connect with a certain witch (Bonnie?) while trying to deal with how to cope with their supernatural abilities.
Nothing has been confirmed, so we do not know if it is an official and/or true information.
There are rumors that these spoilers are fake. They were sent to us by someone claiming to have seen them on E News and they sounded completely logical so we posted them so take them with a grain of salt.
Source: Spoiler TV