Caroline (Candice Accola) wakes up in the hospital after Katherine (Nina Dobrev) killed her and she is hungry.
Elena doesn't want to talk about vampires or Damon (Ian Somerhalder) especially after he killed Jeremy (Steven R. McQueen).
Meanwhile, Stefan (Paul Wesley) gives Jeremy a jewel that contains vervain and explains him that it will protect him from compulsion.
Damon accepts her offer when Tyler (Michael Trevino) and Mason (Taylor Kinney) return home.
Matt notices her strange behavior especially when he tries to open the curtains and Caroline jumps to the other side of the room demanding that he close them.
The nurse, who enters at that moment, takes the necklace to give it back to her but Caroline attacks her and drinks from her, after she compels her.
Damon compels Carter to pick a fight with Tyler in order to finally find out what the Lockwoods are.
Caroline also compelled her with a story about the bite on her neck and leaves to go check on Elena and Bonnie at the carnival.
Mason intervenes to stop them, he vaults over a car and leaps ten feet into the air before he lands on all fours.
Tyler sneaks away and opens the secret safe at his dad's office where he finds, among documents and other things, the moonstone Mason is looking for and takes it.
He came to kill him but changed his mind and warns Damon not to drink from the whiskey bottle since he put vervain in it.
Jeremy says his father and his uncle hated vampires because they were taught to, but he realizes that killing Damon wouldn’t solve anything.
He takes her back to the now closed carnival and then jumps with her to the top of the Ferris Wheel where they admire the view and kiss.
Steve Marsi of TV Fanatic rated the episode with 4/5 praising the acting of the secondary characters of the show: "There's a new vampire in Mystic Falls, one quite unlike any we've seen to date.
"Brave New World" fleshed out all of these components as brilliantly as we've come to expect, thanks to surprisingly strong acting from a CW series.
"A lot of time this episode is spent with the Lockwood family "secret", which may be unknown to the characters on the show, but is pretty clearly about werewolves.
"[4] Robin Franson Pruter of Forced Viewing rated the episode with 3/4 saying that Candice Accola shines as a new vampire.
It’s so cliché, and it’s been done before" [...] And then, moments (well, sometimes minutes) later, I realized that I should sit back and trust the man who brought us the Scream franchise.
"[6] The TV Chick gave a B+ rate to the episode saying: "I liked it a lot, but I want to leave room for more awesomeness ahead.
It definitely opened up some interesting paths for us (Damon the head of the council, werewolf madness, Caroline and Stefan’s Mr. Myagi/Ralph Macchio relationship).
"[8] Den of Geek gave a good review to the episode saying: "All in all, Brave New World really made me look forward to where the story is taking us and what the future holds for our favourite residents of Mystic Falls.