With help from Elena and Bonnie, Alaric tries to decipher the meaning behind his recent discovery Elena and Rebekah engage in a mean-girl power struggle, until Rebekah finally reveals some of her family's ancient secrets and the violent past she shares with Klaus and Elijah. Damon tries a reckless new approach to make a breakthrough with Stefan, and they're both surprised by an unlikely ally.

Sheriff Forbes delivers some disturbing news to Alaric and Elena about the weapon used in a recent murder. In the Salvatore brothers’ escalating quest to kill Klaus, Stefan turns to Bonnie and Abby, while Damon reaches out to an old acquaintance for help in setting up an elaborate plan. Intent on a plan of his own, Klaus hosts a strange dinner party, where he reveals another story from his family’s violent past until an unexpected guest brings the party to an end. Meanwhile, Caroline is heartbroken when she is unable to stop a tragedy from unfolding.

Elena is surprised to receive an invitation to a formal ball, and when Damon and Stefan hear the party is being hosted at Klaus’s newly renovated mansion, they both insist on attending the event with her. Caroline and Matt also receive invitations to the ball from unexpected admirers. At the elegant party, Elena learns of a horrifying plan that could lead to numerous deaths and she must decide who she can trust with her new information. Caroline discovers a side of Klaus no one would have suspected. Finally, after an evening of violence and dashed hopes, Damon finds a new way to cope.

After starting her day with a startling discovery of Damon’s latest indiscretion, Elena is frustrated to find that none of her friends agree with her on how they should react to the Original family’s internal power struggle. Once again caught up in the destiny of the Bennett witches, Bonnie and Abby find themselves playing a part in a ritual to appease the spirits of nature. When Elijah gives Damon and Stefan a dangerous ultimatum that puts Elena in danger, they turn to Alaric and Meredith for help with a plan that leads them to a terrible choice.

Elena and Damon set off together to make sure Jeremy is safe in Denver, and to see if his special abilities can help reveal the information they need about ancient vampire bloodlines. It doesn’t take them long to learn that Jeremy has been hanging with the wrong people. Stefan and Klaus both go to brutal extremes in their search for the missing weapon. Caroline is thrilled when Tyler returns to town, but Tyler soon suspects that something has been going on between Caroline and Klaus. Matt has his hands full trying to keep Rebecca busy organizing the school’s upcoming 1920s Decade Dance.

Alaric finds an unexpected ally to guide him on his dangerous new path, while Damon and Meredith try to figure out what their next move should be. At the school’s 1920s Decade Dance, Bonnie asks Jamie to go with her and, at Caroline’s suggestion, Elena asks Stefan to be her date. Caroline is pleasantly surprised when Tyle shows up at the dance determined to sweep her off her feet, but Klaus does his best to come between them. The dance takes a deadly turn when Damon and Stefan realize they need the help of Matt, Jeremy and especially Bonnie to undo a spell that could prove devastating for everyone.