After learning that someone from Stefan’s past may be Damon and Enzo’s next target, Stefan, Bonnie and Caroline head to North Carolina. There, Bonnie takes drastic measures in an attempt to break Enzo free of whatever has a hold over him. At the Armory, Alaric and Georgie stumble upon a mysterious symbol that may be related to the supernatural force controlling Damon and Enzo. Finally, Caroline gets an unexpected surprise from Stefan.

Spiraling down a dangerous path of self-destruction, Damon’s latest actions prove he may be beyond the point of return. Unwilling to give up on his brother, Stefan is forced to make a gut-wrenching decision that threatens to change their relationship forever. Elsewhere, Bonnie gets advice from Caroline on how to break through to Enzo, while Matt attempts to decipher a mysterious box of messages that he’s received. Finally, after tragedy strikes close to home, Stefan and the others are forced to remember what matters most to them.

Klaus and Stefan arrive in Chicago, where Stefan is reunited with a vampire who hasn't really moved on from her interest in him decades earlier. In a flashback to Chicago in the 1920s, Stefan comes face-to-face with a shocking chapter from his wild past. After Damon gets a tip on Stefan and Klaus' whereabouts from an unexpected source, he and Elena follow their trail. Back in Mystic Falls, Tyler is concerned about Caroline and turns to Sheriff Forbes for help.

Faced with the fallout from his interaction with Cade, Stefan is determined to have one thing go right – Christmas Eve with Caroline. However, when Damon and Sybil crash their Christmas Eve dinner, which had been joined by Alaric, Matt and Peter, things quickly take a dark and twisted turn. Meanwhile, in a series of flashbacks to Stefan’s past, Cade’s attempt to entice him with his mysterious agenda leaves Stefan faced with an unimaginable decision.

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.

Damon and Stefan must join forces against Cade in order to save Elena’s casket. Meanwhile, Caroline and Alaric deal with their daughters’ burgeoning magical powers.

A century after their first encounter, Damon and Sage meet again at the ceremony to kick-off the restoration of Wickery Bridge. Damon is surprised to learn the reason Sage has returned, and pleased when she devises an unusual method to help him figure out what Rebekah is up to. Abby is having a hard time adjusting to her new reality, despite Bonnie and Caroline’s efforts to help. When Damon informs Elena of Stefan’s latest struggles, she reaches out to Stefan to help her save a friend in danger, in hopes that it will help bring Stefan even closer to his humanity. Finally, when Damon discovers a new secret weapon, he lets Stefan in on the news.

Stefan and Damon attend an anger management support group looking for their next victim. Sybil is still alive and teaching a group of high school students who she’ll later use as leverage to get Caroline to locate a historical artifact that can be used against her. Meanwhile, Stefan and Damon continue their commitment to Cade as they test the morals of a young doctor, Tara.

Stefan and Damon return to Mystic Falls at Sybil’s request as she is still in search of the historical artifact. Bonnie returns from Paris wearing a vile of Enzo’s blood making Caroline, wonder if she will become a vampire. Stefan, Damon, Caroline, Bonnie and Enzo all attend the Miss Mystic Falls pageant where Sybil continues to taunt Damon with memories of Elena.

Sybil enacts revenge on Damon by putting him in a catatonic state. Caroline and Bonnie enter Damon’s mind and run into familiar faces from the past, only to discover Stefan is the key to Damon’s fate. It’s a race against time for the bell as both Sybil and her sister Seline jockey for its control.

In order to save Stefan’s soul, Damon makes a deal with Cade to retrieve the Maxwell journal. Alaric and Matt refuse to hand the journal over as it may contain the key to destroying Cade. Caroline desperately tries to connect with Stefan before Cade goes through with his plan.

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.

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.

As Enzo continues to fight the control over him, Bonnie finds herself at the center of a deadly game and forced to make a heart wrenching decision involving two of the most important people in her life. At the Armory, Alaric researches a mysterious artifact that he hopes will help in their fight to get Damon and Enzo back. Finally, Damon’s downward spiral leads him to Tyler Lockwood who attempts to talk some sense into him before it’s too late.

Tasked with finding a mysterious artifact, Damon’s latest mission takes him to Texas where a violent run-in with Peter Maxwell leads to a surprising revelation. Meanwhile, after gaining the upper hand in their fight to save Damon and Enzo, Stefan and Alaric team up and uncover the origins of the mysterious force they’re up against. Finally, Matt returns to the fray after his past and present collide in an unexpected way.

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.

Cade returns to Mystic Falls and presents Damon and Stefan with additional assignments, each with unthinkable consequences. Even with tension growing in their friendship, Caroline and Matt do their best to protect the town’s residents from Cade’s appetite for their souls. Bonnie and Enzo hit the road on a romantic trip, taking the bell with them in hopes to keep it safe.

Damon and Alaric come face to face with an old enemy after they obtain a weapon that may be able to destroy Cade. Stefan is held captive by a surprising acquaintance and is forced to confront a dark secret from his past. Meanwhile, Caroline and Matt try to keep Stefan’s violent history from destroying him. Cade focuses his attention on Bonnie and digs deep into her mind.

As Mystic Falls gets ready for a festival to celebrate the passing of a comet, Vicki continues to recover in the hospital following Damon's attack. Stefan heads to the hospital to try to use his abilities to make Vicki forget who attacked her, but his efforts are cut short by Matt. Meanwhile, at a parent/teacher conference Mr. Tanner tells Aunt Jenna that Jeremy is in trouble and needs immediate intervention.

Klaus puts a plan in motion that will give him even more power, but even with the unwilling participation of werewolf Ray Sutton, things don’t go exactly as Klaus had planned. Damon and Alaric reluctantly go along with Elena’s new strategy to find Stefan, leading Damon into a dangerous fight with an unexpected enemy. Jeremy turns to Matt for help as he continues to try to understand what the ghosts from his past want from him. Unaware that Caroline is in need of his help, Tyler faces an emotional confrontation with his mother.

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.

The present-day murders in Mystic Falls remind Damon of a similar crime spree a century earlier. In flashbacks to 1912, Damon recalls a beautiful vampire, Sage, who showed him a whole new way to exist. Sheriff Forbes warns Damon not to get involved in her investigation, but Damon is convinced she’s going after the wrong suspect. Elena and Matt resort to breaking and entering in their search for evidence to prove Dr. Fell is a murderer. For reasons known only to her, Rebekah, becomes interested in locating one of the town’s oldest landmarks. Finally, Elena comes to a new understanding of the path her life has taken, and Damon makes an emotional confession to Stefan.

On the first day of their senior year, Elena, Caroline, Bonnie and Matt are still reeling from recent events, while Tyler seems to be enjoying everything a little too much. Damon is annoyed by a new houseguest, and everyone is surprised by the arrival of a new student in Alaric's history class. Matt asks Bonnie for help when he realizes he made a serious mistake. Meanwhile, Stefan continues to carry out his latest assignment from Klaus.

Damon and Caroline suspect Stefan and Elena of keeping a secret while they hide from the travelers, unaware of the dead man out for revenge. Meanwhile Matt, Jeremy and Bonnie help Tyler get rid of Julian.

When Enzo’s efforts to protect Bonnie end up putting her life in jeopardy, they learn that Rayna may hold the key to her survival. With time running out and Rayna at the reins, Enzo and Bonnie reluctantly team up with Damon, who is desperate to save Bonnie’s life and to repair their broken friendship. Elsewhere, when Stefan travels to Dallas and comes face to face with Alaric, tensions escalate and they are forced to confront the fallout from Stefan’s absence in Caroline’s life. Finally, Enzo learns The Armory’s true motives behind their search for Bonnie.