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.

An Ancient Presence In Mystic Falls, Stefan and Damon come to Elena’s assistance and, in the process, learn surprising new information about people, vampires and events in the distant past. Jeremy helps Bonnie after she casts a difficult and exhausting spell, and Caroline does what she can to make things easier for Tyler. Finally, Stefan and Damon reach a new understanding.

Stefan and Elena get away for what they hope will be a romantic weekend at the Gilbert family lake house, not realizing that they’ve been followed. Jenna starts to worry that Alaric isn’t being honest with her. Jules explains the importance of the sun and moon curse to Tyler, but leaves out an important detail. Damon attends a tea at the Historical Society in order to talk to Elijah, but Elijah isn’t giving up any secrets. With help from Caroline and Jeremy, Bonnie uses deceptive measures to get shocking new information out of Luka. Finally, Tyler offers Matt some relationship advice.

Damon is willing to go to extraordinary lengths to prevent Elena from being a victim of Klaus’ plan to break the curse. Damon’s actions put him at terrible odds with Stefan and the tension that started brewing between the brothers over their differing opinions of how to help save Elena’s life blows up into full-scale conflict. Tyler returns to Mystic Falls after receiving a disturbing phone call. With the full moon marking the arrival of the sacrifice ritual, Stefan and Elena spend a romantic day together — afraid it might be their last.

Still in Chicago, Klaus uses Gloria, a witch he knew long ago, to help him track down missing information that will explain why his plan isn’t working. Gloria’s spells reveal intriguing glimpses of the truth, but she soon realizes she needs Stefan’s knowledge to complete the puzzle. When Stefan suddenly finds himself in danger, help comes from a surprising ally. Back in Mystic Falls, a frustrating new enemy pushes Damon over the brink and he lashes out in a way that will have lasting consequences. Caroline struggles with her own emotional issues, even as she tries to help Elena face her feelings. Jeremy makes a brief but disturbing breakthrough with one of his ghostly visitors, leaving him more confused than ever. Finally, Bonnie has a strange encounter that will affect everyone.

Bonnie believes her recurring dreams about Klaus’ coffins will tell her how he can be killed. The dreams also lead Bonnie to a reunion with her mother, Abby, whom Bonnie hasn’t seen for 15 years. At Abby’s remote farmhouse, Bonnie and Elena meet Jamie, the young man Abby took in years earlier. Bonnie’s sudden appearance catches Abby off-guard, but she does her best to explain the past. Tyler turns to an unexpected ally in his quest to regain his free will. Damon is intrigued by Alaric’s new friend, Dr. Fell, and Klaus continues his bitter negotiations with Stefan over control of the coffins containing his family members.

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.

Connor continues his search to uncover the secrets of Mystic Falls and tries to convince Jeremy to work with him. With Dr. Fell’s help, Damon and Klaus question Connor, but the confrontation takes a lethal turn. Trying to keep her new life as normal as possible, Elena is determined to continue her senior year at Mystic Falls High with support from Matt and Caroline. Rebekah’s arrival at school makes it difficult for Elena to control her anger, but she learns that confronting Rebekah can be extremely dangerous. Later, Rebekah realizes how alone she is, and reaches out to April. Stefan takes Elena on a thrilling motorcycle ride in an effort to show her that life can still be fun. Tyler gets a surprise visit from Hayley, a werewolf who helped him through the ordeal of breaking his sire-bond to Klaus. Concerned about Elena, as well as his own emotions, Stefan turns to a sympathetic Caroline for advice.

When Damon and Bonnie realize that uncovering a time in Damon’s past may provide clues to finding their way home, Damon is forced to relive one of the worst days of his life. After an awkward run-in with Jo at the hospital, Alaric steps in to help Jeremy get his life together and cope with the loss of Bonnie. Elsewhere, Stefan attempts to show Elena what it’s like to start over and create a new identity, while an unsuspecting Matt finds himself in a disturbing situation when Tripp lets him in on a dark secret. Lastly, Stefan, who is desperate to regain some normalcy in his life, is stunned when an unexpected visitor shows up.

When an impulsive decision by Damon threatens to unravel a carefully negotiated deal between Stefan and Lily, he has no choice but to make amends with his mother before things spiral further out of control. However, Lily remains one step ahead and carries out a harsh plan that hits Damon where it hurts most.

Elsewhere, after returning to Whitmore Collage, Alaric turns to Bonnie for help with a mysterious and potentially dangerous artifact he has obtained, while Matt is forced into making a risky life or death decision. Meanwhile, Caroline, who finds herself a pawn in Lily and the heretics' plan for retribution, uncovers a shocking detail about Stefan's past.

With the holidays in full swing, a search for Julian leads Damon and Stefan to a small town outside of Mystic Falls. While managing a holiday toy drive at Whitmore College, Bonnie seeks help from Nora and the two strike up an unlikely friendship.

Elsewhere, Caroline does her best to navigate her new life as a pregnant vampire, while Alaric grows concerned that the pregnancy is effecting her more than she's letting on. Finally, after finding himself at odds with Damon, Stefan is forced to take matters into his own hands, setting off a tragic chain of events that leaves their lives changed forever.

While Stefan and Valerie search for a magical herb that can keep him hidden from Rayna, Damon comes up with his own plan to take her down for good. However, while at The Armory, Bonnie makes a shocking discovery about Rayna that brings Damon’s plan to a screeching halt.

Elsewhere, a conversation with Caroline leaves Stefan questioning their future together, while Matt decides it may be time to truly take a stand against the vampires of Mystic Falls. Finally, as the season’s middle chapter draws to a close, Damon’s desire to take himself out of the game ramps up as he races to complete unfinished business with Stefan and Bonnie.

Despite their best efforts to help Bonnie through the harrowing predicament she now faces, Damon, Enzo and Caroline realize their options are running out and drastic measures need to be taken. With their only chance of saving their friend lying inside the Armory, Stefan breaks the news to Caroline that they may need help from an unlikely source – her and Alaric’s twin daughters.

Elsewhere, Enzo keeps Bonnie preoccupied by bringing her back to their cabin but when his plan takes an unexpected turn, it’ll be up to Damon to make the ultimate sacrifice to save his closest friends.