After shutting off her humanity following the death of her mother, Caroline gives her friends an unexpected ultimatum. Not knowing how to handle the new Caroline, Stefan's attempt to intervene sets off a dangerous chain of events, leaving him and Elena in a race against the clock. Meanwhile, after seeking answers from Kai about the prison world, Damon's world is turned upside when he learns some devastating news about his mother Lily. Elsewhere, Enzo finds himself becoming increasingly intrigued by Sarah Salvatore, and Bonnie begins to struggle with the effects of being back in the real world.