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.

After discovering that poachers have begun taking out werewolves in the bayou, Elijah and Jackson grow concerned for Hayley's safety when she fails to show up during the full moon. Meanwhile, Davina, the only one with the answer to Hayley's whereabouts, plots ways to use that to her advantage. Elsewhere, Cami approaches Klaus with her theory on who is behind the series of murders in the French Quarter, while Lucien delivers to Elijah an unsettling warning about the war brewing among the sire lines. Finally, after receiving a dire prophecy about the future of the Mikaelson siblings, Klaus takes extreme measures to determine the validity of this potential impending threat.

With tension running as high as ever, Klaus and Elijah are forced to come together in order to uncover Lucien’s true motives in New Orleans. Cami is caught off guard when she finds herself face to face with Lucien and is surprised when he reveals some unexpected information about his past with Klaus. Elsewhere, a mysterious figure presents an enticing offer to Marcel, while Hayley turns to an unconventional way of coping with her current situation. Finally, an old acquaintance from Elijah’s past arrives in New Orleans and delivers some startling news involving the growing threat to the Mikaelson siblings.

In order to uncover what his old acquaintance Tristan is really up to in New Orleans, Elijah considers attending a gala thrown by a mysterious group of ancient vampires known as The Strix, while Hayley invites herself to attend with him. There, Marcel is approached with an enticing offer made by a mysterious woman named Aya, but he quickly realizes that things are not always what they seem. Elsewhere, when a vital component of Lucien's plan goes missing, he and Klaus form a tentative alliance in order to find it.

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.

With a dire prophecy looming over them, Klaus and Elijah invite Lucien, Tristan and Aurora to a Thanksgiving gathering in an attempt to negotiate a truce. When Aurora reveals that she has powerful leverage over Klaus, Hayley and Freya take matters into their own hands, leading to a deadly three-way confrontation. Elsewhere, Marcel and Vincent are forced to take drastic measures when they realize Davina may be in over her head, and Cami finds herself face-to-face with a dangerous new threat.

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.

In the aftermath of a horrific plan that left Cami dead, Klaus declares war on Aurora and Tristan. Elsewhere, Vincent, who has resumed his role as Regent to the New Orleans witches, is forced to use his magic against his will, while Hayley and Jackson ind themselves pawns in Tristan’s twisted game. Finally, after learning that Tristan is in possession of a powerful weapon that could take their family down once and for all, Klaus, Elijah and Freya enact a risky plan that leads to a tense showdown with The Strix.

When a powerful weapon that could take down the Mikaelsons for good ends up in the wrong hands, Klaus finds himself in a tense standoff with an unlikely foe. Meanwhile, Elijah's attempt to reclaim control of The Strix leads to a violent showdown and the emergence of a potential new leader. Elsewhere, when a new coven of witches tries to influence Davina into helping them locate the elusive weapon, she quickly realizes she may be in over her head.

With the threat of the prophecy looming over their heads, Klaus and Elijah find themselves rendered useless inside a magical trap, while Aya and The Strix's coven of witches move forward with a risky spell that could take one of them down for good. Elsewhere, Freya leads the charge to get her brothers back and enlists the help of Marcel, Hayley and Stefan Salvatore, an old friend of Klaus', whose unexpected arrival may be the key to their survival. Finally, Davina moves forward with a dangerous plan that brings her one step closer to reuniting with Kol.

The crossover starts on The Vampire Diaries S7E14 Moonlight on the Bayou (I).