After a twisted plan left the life of his girlfriend Elena linked to that of his best friend Bonnie, Damon is forced to navigate his new reality without the love of his life. A newly empowered Bonnie has decided that she will be Damon's moral compass and keeps a close eye on him as he, in turn, cautiously keeps tabs on Alaric, following the loss of his fiancée Jo. Meanwhile, as he waits for Caroline to sort out her emotions, Stefan takes an active role in protecting the town from Lily and her family of Heretics, who have wasted no time wreaking havoc in Mystic Falls.

Elsewhere, Enzo struggles to find his place in Lily's new life, and is quickly forced to decide where his true loyalties lie. Finally, with the stakes higher than ever, Matt, who has recently completed his deputy training program, teams up with Stefan and Caroline to put a stop to the Heretics, but an unexpected turn of events leaves one of them in a dangerous position.

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.

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.

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.