When a confused and desperate Caroline leaves the hospital and joins her friends at the Mystic Falls Carnival, Damon wants to take immediate action, but Stefan and Elena come to Caroline's defense. Matt is completely mystified by Caroline's behavior, but still tries to tell her about his feelings for her. Damon has suspicions about Tyler's Uncle Mason and uses Tyler's volatile personality in an attempt to get Mason to reveal his secret. Upset with everything going on around her, Bonnie takes her anger out on Damon.

Stefan takes drastic measures to find out the real reason Katherine has returned to Mystic Falls, and is shocked when she reveals new secrets about what really happened in 1864. Damon tries a new tactic to resolve his issues with Mason,, but it proves costly. Tyler pushes Mason to tell him the truth about the Lockwoods. Finally, when Katherine delivers an ultimatum, Stefan and Elena are left with very few options.