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.

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.

Elena’s new outlook has everyone concerned, leading Stefan and Damon to agree that going back to the normal routine of high school would be the best thing for her. Caroline is pleasantly surprised when Elena decides to rejoin the cheerleading squad, but her pleasure turns to shock when Elena’s behavior proves dangerous. Not giving up on their search for the cure, Damon and Rebekah work together until his unwanted advice catches her off-guard. Klaus tries to use Hayley to get the information he’s after and makes an intriguing discovery in the process. Meanwhile, a bored Elena throws a wild party and gets into an ugly fight.

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.

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.

Elena and Caroline plan a big party at school, but their plans are interrupted when Jesse suddenly needs Caroline's help. Meanwhile, Damon makes a terrifying discovery about a secret society.

Caroline convinces Elena and Bonnie to attend Whitmore College's Bitter Ball for broken-hearted students. Bonnie meets a fellow student who appears to be dabbling in witchcraft. Tyler worries about Matt's relationship with Nadia. Damon and Enzo resort to violence to convince Bonnie and Jeremy to help them get revenge, but their plan takes a horrifying turn.

Damon tries to find the right way to make a disturbing confession to Elena. Caroline discovers a scary secret in Dr. Wes' files. Enzo claims to have a solution everyone is searching for. Sloan reveals new information on the importance of doppelgangers.

After spending the past four months coping with the loss of Damon in an unconventional and potentially dangerous way, Elena has returned to Whitmore College for the start of sophomore year. Unable to move on, Caroline is desperate to find a way to reverse the anti-magic spell the Travelers have put over Mystic Falls and grows frustrated when her calls to Stefan go unanswered. Tyler, who is human once again, has a run-in at a football tailgate that tests his ability to control his anger, while Matt worries that Jeremy is dealing with the loss of Bonnie in a self-destructive way. Alaric, who is struggling to adjust to his new life as a vampire, finds himself in an awkward situation when he meets Jo, a beautiful doctor at the university hospital. Last, while everyone believes Stefan is off tracking a lead to get Damon and Bonnie back, Elena is shocked when she learns the truth of what he has really been up to.

With their humanity turned off, Stefan and Caroline begin wreaking havoc at Whitmore, leaving Damon to come up with a risky plan involving Lily. After rushing to help Jo treat victims of Stefan and Caroline’s latest killing spree, Elena discovers Jo is pregnant, prompting her to reevaluate her own life as a vampire. Meanwhile, when Sarah boldly turns the tables on an unsuspecting Enzo, he is forced to open up about his tragic past. Lastly, at Scull Bar, a twisted round of karaoke leaves Tyler and Matt in a dangerous situation.

With the traumatic effects of the Phoenix stone taking a toll on his brother, Stefan attempts to help Damon regain his grip on reality, while secretly struggling with his own experience in the stone. Elsewhere, Matt and Bonnie deal with the fallout after Julian and his men take over Mystic Falls, leading Matt to spiral out of control and into trouble with an officer named Penny. Meanwhile, Tyler returns to town for Alaric's baby shower and Caroline makes an upsetting discovery involving Alaric and his future plan for the babies.

Determined to capture an escaped vampire named Ambrose, who may be the key to getting Stefan back safely, Damon heads to Memphis with Alaric in tow. However, reluctant to step back into his former vampire hunting ways, Alaric makes his unwillingness to participate clear, while revealing the truth about the past three Damon-less years of his life. Meanwhile, in the psych ward, Bonnie meets a young woman named Virginia, who provides her with some valuable information about why The Armory may be after her. Finally, Enzo takes matters into his own hands when he learns some devastating news from Rayna.

With Bonnie's life at stake and an uphill battle ahead of them, Damon and Enzo lead the charge to save Bonnie before her condition worsens. Stefan reluctantly teams up with Matt for the sake of Bonnie and uncovers the truth behind Matt's anger towards him. Elsewhere, determined to help her best friend, Caroline joins Alaric on a mission and quickly realizes how much she's missed her former supernatural lifestyle. Finally, after their plan takes an unexpected turn, Damon makes a fateful decision that will forever change his relationship with Bonnie.

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.

Elena Gilbert and her brother Jeremy come to terms with the death of their parents. Elena is popular amongst her peers and the perfect straight A student, but has difficulties hiding her grief from the world. Meanwhile, Jeremy treads on a dangerous path of using drugs to ease his pain. The arrival of new student Stefan Salvatore, however, makes Elena think about romantic possibilities.

A fellow Whitmore student named Jesse gives Elena some intriguing information about Professor Wes Maxfield. Damon asks for help finding Stefan.

Elena meets a sad and secretive student on campus. Elena and Damon attend the Whitmore Historical Ball dressed as Anne Boleyn and Henry VIII. While there, Elena receives a disturbing message from Dr. Maxfield. Nadia reveals her surprising history to Katherine;. Silas demands that Damon commit an unthinkable act.

Damon is forced to deal with a part of his past he thought was gone forever when Dr. Wes unleashes a secret weapon to stop him from rescuing Elena. Elena learns about the dark history of Whitmore College. Katherine turns to Matt for help.

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.

Damon's behavior escalates from destructive to deadly. Stefan begins to regret their last conversation and tries to track Damon down and intervene. Dr. Wes enlists the Travelers to set a trap that will test Damon's friendship with Enzo; and a talk between Caroline and Stefan leads to a horrifying realization.

Stefan and Elena experience unsettling dreams of the life they might have had together. Bonnie has a disturbing encounter with Grams. Enzo searches for a woman he loved decades ago. Bonnie learns that Jeremy is working with Liv. Matt has a terrifying encounter with inhabitants of the Other Side.

Enzo holds Elena, Stefan and Bonnie hostage to uncover the truth about the love of his life. Markos performs a ritual to undo witch's magic.

In an attempt to bring some fun back into their lives, Elena persuades Caroline to meet her at the swimming hole where she plans to introduce her to Liam. Tyler, still working on controlling his anger issues, asks Liv for a favor and is surprised when she makes an unexpected confession. Stefan arrives back in Mystic Falls looking for Enzo and is caught off guard when he notices a strange change in Elena. Meanwhile, at the lake, Enzo’s actions cause Matt to make a startling revelation, and Jeremy makes a discovery about the anti-magic spell that could potentially put Elena’s life in danger. Elsewhere, Damon and Bonnie stumble upon clues that lead them to believe they’re not alone.

As Alaric and Jo reluctantly participate in their bachelor and bachelorette parties, Damon and Elena discuss the ramifications from an impulsive offer that Damon makes. Unsure of what to do, Elena turns to Bonnie and Jo for advice, but is left conflicted when Bonnie raises some unanticipated concerns. When Enzo realizes Lily is on a dangerous downward spiral, he asks Stefan to help intervene before it’s too late. Lastly, fed up with the supernatural threats that plague their town, Matt takes his frustrations out on Tyler, while Alaric considers a life-changing piece of advice.