On campus, Elena is touched by a sad and secretive student named Aaron. Elena and Damon attend the Whitmore Historical Ball dressed as Anne Boleyn and Henry VIII. At the ball, Elena shares a dance with Dr. Maxfield, who has a disturbing message for her. Caroline's evening at the ball takes her from happiness to heartbreak. Meanwhile, Nadia reveals her surprising history to Katherine, and Damon tries to make a deal with Silas. But when Silas demands that Damon commit an unthinkable act, it leads to a violent confrontation.

Damon and Elena are skeptical of Silas's new goal; Tessa realizes she was outsmarted by Silas; after discovering a new consequence of becoming human, Katherine decides she needs a new place to stay; Bonnie is impressed with Jeremy.

At Whitmore College, Elena and Caroline decide it's time to throw a big party, but their plans are interrupted when Jesse suddenly needs Caroline's help. At Elena's request, Damon comes up with an effective method to get Wes to answer his questions. At the party, Elena finds that she and Aaron have a lot in common, and Caroline grows more concerned about Jesse. Meanwhile, Katherine does a favor for Matt and manages to get through to Stefan, who is still struggling to overcome the events of the summer. Finally, Bonnie does her best to cope with her new reality, and Damon makes a terrifying discovery about a secret society.

Damon is trapped by Dr. Wes, and realizes scary things about his past.

Damon realizes Elena is in danger and enlists Stefan's help to find her. The brothers pay a visit to Aaron, and Damon shocks Stefan by revealing his first-hand knowledge of Aaron's family. In an attempt to stop Damon, Dr. Wes unleashes his secret weapon, forcing Damon to deal with a part of his past he thought was gone forever, as well as the consequences of his decades-long plan for revenge. Meanwhile, Elena is horrified by Dr. Wes' confessions about the dark history of Whitmore College and his own ultimate goal. Finally, a frantic Katherine turns to Matt for help, until she realizes that Nadia may be the one who can solve her problem.

Damon tries to get back together with Elena, however, Katherine has a plan and attempts to take Elena's body permanently. Tyler is upset with Caroline and Matt is used by Katherine. Enzo finds Damon and they decide to become a team again.

Hoping to help everyone move past recent traumatic events, Caroline convinces Elena and Bonnie to attend Whitmore College's "Bitter Ball" for broken-hearted students. Bonnie is intrigued with a fellow student named Liv, who appears to be dabbling in witchcraft. Tyler starts to worry about Matt's relationship with Nadia. After making a disturbing discovery, Stefan has a frustrating conversation with Damon and Enzo. Dr. Wes struggles to continue his research project with help from a new benefactor named Sloan. Still bent on revenge, Damon and Enzo resort to violence to convince Bonnie and Jeremy to help them, but their plan takes an unexpected and horrifying turn.

Damon tries to figure out how to make a disturbing confession to Elena.