Rebekah arrives in New Orleans at her brother Elijah's insistence, but, concerned that Klaus is up to no good, she seeks help from a reluctant Sophie. Marcel enlists Davina's help.

Klaus goes to extreme measures to protect Hayley and their unborn baby when he learns Hayley's life is being threatened. Meanwhile, Cami turns to Father Kieran for guidance. Marcel seeks advice from an old friend. Davina tries to control her magic.

Davina becomes violently ill and the repercussions affect the entire French Quarter. Sophie delivers some startling information about the harvest festival and presents a drastic plan to save Davina. Hayley, racked with guilt, confesses to Elijah about her role in Sophie's plan.

Rebekah and Marcel have been trying to keep a secret from Klaus which may come to the light as we flashback to 1919. Elijah and Monique bond. Hayley takes Sabine hostage to try and get information on reversing the curse on her clan.

Hayley atempts to save her unborn baby from the witches. Francesca meets with Oliver and Jackson to decide the future of the werewolves in New Orleans.

In order to show Elijah that her plan is what's best for him, Esther forces him to relive a time long ago when he loved a young woman named Tatia.

Finn captures his brother's spirits, while the vampires remain trapped and their hunger grows.

Klaus must put aside his mistrust for Freya in order to save Rebekah's life.

With time running out, Klaus' ultimate plan to protect baby Hope at all costs continues to take shape.Source: CW

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.

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.

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).

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.

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.