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.

After realizing the downward spiral he was on, Damon decides he’s going to turn over a new leaf and that his actions moving forward will do right by Elena. Lily prepares for the arrival of a special figure from her past, while Enzo stands by not sure what to expect.

Elsewhere, at Caroline’s urging, Stefan comes face-to-face with Valerie and learns some upsetting details about her past, while Enzo and Bonnie find themselves at odds when they’re forced to fend off a violent threat. Finally, when Bonnie learns some disturbing information involving the Phoenix stone, she is forced to confront Alaric.

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.

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 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.

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.

After finding himself on the wrong end of Julian's plan to avenge Lily's death, Damon awakens to find himself trapped inside the Phoenix stone, tormented by a traumatic experience from his time in the Civil War and forced to face his darkest demon in order to get out. On the outside, Bonnie is in a race against the clock to get Damon out before the effects of the Phoenix stone take over and leave him changed forever.

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.

When his experience in the Phoenix stone leads him to do the unthinkable, Damon finds himself without a care in the world, spiraling out of control and under the influence of a dangerous and reckless Julian. Refusing to give up on his brother, Stefan attempts to reason with Damon only to uncover the devastating reason for his descent.

Elsewhere, Caroline begins having some dangerous side effects as a result of her supernatural pregnancy and is forced to turn to Valerie for help. Meanwhile, Bonnie, Nora and Mary Louise attempt to track down a ruthless vampire hunter named Rayna after they suspect that she has reemerged.

When complications from her supernatural pregnancy leave Caroline's life hanging in the balance, Stefan and Valerie take extreme measures to try and save her and the babies. Meanwhile, after uncovering a dark secret about Damon, Enzo uses the information to force Damon into helping him track down Rayna Cruz, a ruthless vampire hunter who is on the loose. However, when Damon's actions inadvertently put everyone he loves in Rayna's path, he is forced to make things right before it's too late.