Plot summary
Klaus and Rebekah realize Connor is one of "The Five." Bonnie, Elena, and Damon meet Professor Shane, who appears to be a believer in the supernatural. At a party being thrown on campus, Damon teaches Elena how to feed properly. Stefan learns the "Ultimate Weapon" of The Five is a possible cure for vampirism. Connor escapes Klaus by killing one of his hybrids, and leaves to find the one who sent him to Mystic Falls in the first place: Professor Shane.
Credits
Adapted from Wikipedia contributors, The Vampire Diaries season 4. HTML formatting and reference markers removed.