Just as Damon thinks he's gained the upper hand in his fight against Lily, an unexpected turn of events leaves him scrambling for a plan B. Elsewhere, when the fallout of Damon's actions gains the unwanted attention of Mary Louise and Nora, Stefan and Caroline are forced to spend the night distracting the girls at Whitmore College's Heaven & Hell ball. Finally, after suspecting that she's up to something, Enzo sets off on a mission to find out what Valerie is hiding, while a plan set by Alaric and Bonnie leaves their worlds turned upside down.

As Julian and Lily throw a party to celebrate Mary Louise and Nora's anniversary, Stefan and Damon set in motion a risky plan to eliminate a new threat posed by Julian. Meanwhile, following a major revelation uncovered by Valerie, Caroline is forced to face her new reality, even as it threatens to destroy her relationship with Stefan. Finally, determined to do what's best for her family, Lily makes the most difficult decision of her life.

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.

After being reunited with her former love Julian, Lily hosts a dinner party to introduce him to Damon and Stefan and to declare peace between her family of Heretics and the residents of Mystic Falls. Damon and Stefan find themselves at an impasse when they realize they have differing views on how to handle Julian's arrival. At the party, Bonnie and Matt uncover a strange mystery involving some unsuspecting residents, while a devastating revelation causes Alaric to reach his breaking point.

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.

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.

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.

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.

In the aftermath of a clever plan orchestrated by Lily, Damon sets off on a road trip with Bonnie and Alaric in search of leverage they can use against his mother. Meanwhile, Caroline, who is being held hostage by the Heretics, learns some shocking information about Valerie’s past, while Stefan learns a few unexpected details about his own past from Lily. Finally, Alaric turns to Bonnie for her help after coming clean about a secret he’s been keeping.

In order to get through to Lily about Julian's manipulating ways, Stefan and Damon confront their mother with painful memories from their childhood. However, when Lily reveals a dark secret she's been harboring for over 160 years, Stefan and Damon are left questioning everything they've ever known about their family. Determined to prove himself to Lily, Enzo comes face-to-face with Julian and challenges him to a duel, but an unexpected twist threatens to complicate things. Elsewhere, Matt finds himself in the middle of a deepening mystery involving the residents of Mystic Falls, and Caroline's world is turned upside down when Valerie reveals some life-changing news to her.

As Elena tries to ignore Bonnie's warnings about Stefan, Tyler tries to embarrass Stefan by throwing a ball at him. However, his effortless catch and football skills impress everyone, leading Mr. Tanner to let him join the football team. Meanwhile, Elena invites Stefan and Bonnie to dinner in order to try to get the two to know each other, but the night ends up backfiring. Finally, the town is shocked by an act of violence.

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.

In flashbacks, Stefan and Damon recall the long-ago actions taken by townspeople including their father, Guiseppe Salvatore, and Pearl, leading to the devastating events that caused the rift in their relationship. In the present, Bonnie's date with Ben takes a frightening turn. Elena helps Stefan as he and Damon race to find the missing journal that belonged to Elena's ancestor. Stefan learns the reason behind Alaric's interest in both the journal and the town's history. Damon discovers that an old acquaintance has returned to town with an agenda he understands.

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.

Tyler learns more about the Lockwood family curse from Mason. Stefan and Damon argue over how to handle Mason. Elena tries to keep Jeremy from becoming more involved with the Lockwood mystery, but Jeremy makes an effort to hang out with Tyler. Mason gives Sheriff Lockwood some startling information, leading to a night of violence, confession and heartbreak.

As the full moon approaches, Caroline helps Tyler prepare for the transformation he is powerless to stop. While Stefan and Katherine play mind games on one another, Damon and Alaric are suspicious when a stranger named Jules shows up in Mystic Falls, searching for her missing friend, Mason. Elena is frustrated at the lengths Jeremy and her friends have gone to in order to keep her safe. Bonnie and Luca work together on a spell, while still keeping secrets from one another. Finally, Elijah makes an unexpected appearance with an offer that could change everything.

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.

In an attempt to make things right with his brother, Damon offers to have Stefan’s scar magically transferred to him, only to discover that doing so may come with some unexpected consequences. With time running out and Rayna closing in on Stefan, Valerie desperately attempts to reason with Damon before it’s too late. Elsewhere, after being framed for breaking Rayna out of The Armory, Enzo attempts to clear his name, but not before a violent run-in with Nora forces him to make an upsetting discovery.

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.

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.

Elena asks Stefan to escort her to the town's annual Founder's Party. Vicki gets Tyler to ask her to the party, then accuses him of trying to hide their relationship from his family. Zach reveals a useful family secret to Stefan. At the party, Damon tells Elena a story about the Salvatore family's past, leaving Elena with questions that Stefan refuses to answer. Finally, Stefan takes action to get Damon out of his life for good.

While Stefan struggles to come to terms with his past, both he and Damon reveal parts of their history to Elena, until she finally learns the truth about how they became vampires. Pearl has an ugly confrontation with Johnathan Gilbert. Damon and Alaric try to find a mysterious invention before Johnathan does. The friendship and flirtation between Jeremy and Anna continues to grow.