After months of thwarting off dangerous threats and deadly attacks, the Mikaelson siblings finally come face to face with the one person that could lead to their ultimate demise. With the stakes higher than ever and the compound overrun by an army of his oldest sworn enemies, Klaus is put on trial for centuries of atrocities he's committed. Meanwhile, Marcel, who has been spiraling out of control following an act of betrayal by those closest to him, is stunned by the unexpected arrival of someone from his past. Finally, Elijah, Freya and Kol frantically search for a way to save their family before it's too late.

After receiving new visions of the looming prophecy, Freya uncovers that her family is on a collision course with a dangerous new enemy. Meanwhile, with the help of Detective Kinney, Vincent and Kol travel to the ancestral world to put a stop to the witches and take back their city once and for all. Elsewhere, Klaus and Elijah confront Marcel after a heartbreaking plan gone wrong has sent him spiraling.

In the wake of a ruthless plan that has left their family shattered, Klaus, Elijah and Freya desperately search for a way to take down Lucien once and for all. However, their efforts are put on hold following an urgent plea for help from Kol and Marcel. At Klaus' insistence, Freya and Elijah reluctantly stay behind to offer their help, while Klaus and Hayley head to the bayou after uncovering Lucien's latest plan. Once there, an unexpected showdown between Klaus and Lucien forces Freya to take matters into her own hands, setting off a chain of events that will change all of their lives forever.

Following a violent encounter that has left Cami's life hanging in the balance, Klaus is forced to rely on his family and allies to find a cure as he keeps a watchful eye over Cami at the compound. With time running out, Freya turns to her arsenal of spells, while Vincent and Marcel head to Cami's apartment to gather a crucial ingredient. Elsewhere, Hayley and Elijah travel to the bayou in hopes of bringing back a potential antidote that could save Cami's life. Finally, Davina confronts Lucien and learns some heartbreaking information that will change her future with Kol forever.

As the city celebrates its annual Jazz Fest, an unlikely team of Mikaelson foes joins forces to take Klaus hostage. Leading the charge to get their brother back, Elijah and Freya face off against a powerful force like none they've ever seen before, while Hayley and Cami set their own risky plan in motion to rescue Klaus. Meanwhile, when Kol's erratic behavior worsens, Davina has no choice but to turn to Marcel and Vincent for help.

When its 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.

When rumors begin to spread about the remaining white oak bullet, dangerous foes descend upon New Orleans in an attempt to take down Klaus once and for all. As the threats continue to 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, who may have the answers they're looking for. Meanwhile, tensions inside the compound build as Kol is forced to come face to face with his brother Finn, the person responsible for his death. Elsewhere, Klaus and Hayley seek shelter with her former pack and stumble upon some unsettling news involving the threat against them.

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.

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.

Determined to make her ultimate move against the Mikaelson brothers, Aurora uses Freya as bait to lure Klaus and Elijah into a dangerous trap. Meanwhile, after being recruited by The Strix's powerful coven of witches to perform a spell that could save the lives of her closest friends, Davina finds a way to conjure up Kol, the only person who may know the key ingredient to completing the spell. Finally, Hayley is forced to make a heartbreaking sacrifice.

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.

While Klaus finds himself dealing with pressing matters at home, Elijah reluctantly aligns with Aya after learning that she may have knowledge of an elusive weapon that could kill an Original vampire for good. Meanwhile, alone and shunned by her coven of witches, a desperate Davina is left conflicted after she is approached with an enticing offer that could bring her one step closer to reuniting with Kol.

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 find 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 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.

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.

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.

When Elijah and Freya realize that Rebekah may be the target of The Strix's latest plan, they do whatever it takes to protect her. Elsewhere, Klaus spends time with Aurora to figure out where her loyalties lie, while a dangerous run-in with a member of The Strix leads Hayley and Marcel to make an unsettling discovery. Finally, an elaborate scheme created by Lucien leaves Cami faced with a difficult decision to make and Detective Kinney fighting for his life.

KLAUS' PAST COMES BACK TO HAUNT HIM — 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.

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.

FLASHBACKS TO THE FIRST VAMPIRE EVER SIRED — 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.

IMPENDING THREATS AND A DIRE PROPHECY — 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. Marcel and Freya also appear.

Months after 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.