Months following their violent and deadly showdown with the powerful witch Dahlia, a rift continues to divide brothers Klaus and Elijah, while Freya searches for a way to heal their fractured bond and return their family to the way they once were. Meanwhile, Klaus' suspicion piques when he learns that an old vampire friend named Lucien has arrived to New Orleans with a mysterious agenda involving the Mikaelson's remaining sire lines. Elsewhere, Elijah questions whether he can truly forgive his brother for his mounting offenses, while Hayley struggles with being cursed to her wolf form in the bayou. In the French Quarter, Vincent and Cami assist Detective Kinney after a series of gruesome discoveries are made, leading them to believe they may have a serial killer on the loose. Finally, Marcel, who has regained control of the French Quarter once again, tries a new strategy to recruit vampires, while Davina, who is now Regent to the New Orleans witches, makes a decision that will find her and Marcel on opposite sides of an escalating conflict.

As the war among the sire lines continues to grow, Klaus receives an unexpected visit by a figure from his past. When Elijah suspects that Tristan is hiding something, he enlists Marcel's help to find out what he's up to. Elsewhere, Davina struggles with her role as Regent and seeks advice from Hayley. Finally, an ancient secret that is uncovered threatens to tear the Mikaelson brothers apart for good.

After learning that Cami's life is in danger and Aurora may be to blame, Klaus is forced to engage in another one of her devious games and follows a series of clues she's left behind for him. Meanwhile, Elijah, Freya and Hayley take drastic measures against Tristan when they discover he holds a valuable piece of information they need. Elsewhere, Aya gives Marcel an ultimatum that leaves him with a difficult decision to make, while tensions between Hayley and Jackson cause her to reevaluate her involvement in Mikaelson family matters.

When a dangerous affliction threatens to expose one of her siblings, Freya searches for a way to reverse the crippling curse even as she finds herself the target of The Strix's latest plan. Elsewhere, Klaus keeps a watchful eye over Cami while she attempts to help Detective Kinney, whose life has begun to spiral out of control as a result of Lucien's compulsion. Meanwhile, a confrontation with Marcel causes Vincent to reevaluate his decision to stay out of witch business, and Hayley's attempt at a quiet Christmas with Jackson and Hope results in an unexpected surprise.

When Klaus learns that Cortez, an old vampire with a vendetta against him, has arrived in New Orleans, he finds himself forced to deal with this new threat. Meanwhile, when Cortez begins threatening the lives of innocent residents, Vincent has no choice but to help the vengeful vampire in his plan to take down Klaus. Elsewhere, Marcel turns to Davina for her help after several Strix members turn up missing, and Elijah confronts Hayley after learning that she’s been dealing with Jackson’s death in a destructive way.

Dangerous foes descend upon New Orleans in an attempt to take down Klaus once and for all when rumors spread about the remaining white oak bullet. As the threats grow, Elijah urges his siblings to lay low at the compound while Marcel, Vincent and Josh chase down a lead involving a mysterious vampire named Sofya. Meanwhile, Kol is forced to face his brother Finn, the person responsible for his death; and Klaus and Hayley seek shelter with her former pack and stumble upon some unsettling news.

When it's discovered that Freya has been kidnapped and is in the hands of a dangerous new threat, the Mikaelson brothers are forced to put aside their differences in order to save her before it's too late. Following a lead that brings them to Mystic Falls, Elijah and Finn run into deputy Matt Donovan, who does not take well to new vampires in his town. Meanwhile, Klaus and Hayley work together to uncover the motive behind one of Lucien's secret agendas, while a troubling shift in Kol's behavior leaves Davina concerned for their future together.