When his experience in the Phoenix stone leads him to do the unthinkable, Damon finds himself without a care in the world, spiraling out of control and under the influence of a dangerous and reckless Julian. Refusing to give up on his brother, Stefan attempts to reason with Damon only to uncover the devastating reason for his descent.

Elsewhere, Caroline begins having some dangerous side effects as a result of her supernatural pregnancy and is forced to turn to Valerie for help. Meanwhile, Bonnie, Nora and Mary Louise attempt to track down a ruthless vampire hunter named Rayna after they suspect that she has reemerged.

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.

In order to lure a vengeful vampire hunter named Rayna Cruz away from his friends in Mystic Falls, Stefan heads to New Orleans, where Valerie has learned of a safe house that can protect him. Once there, he comes face to face with Klaus Mikaelson, who soon becomes suspicious of his old friend's unexpected arrival in his city.

Meanwhile, Enzo, who is working on behalf of a mysterious organization called The Armory, approaches Damon and Bonnie with a plan that could protect Stefan from Rayna. Finally, after learning that Alaric has decided to leave for Dallas with the twins immediately, Caroline offers to accompany them on the trip and finds herself contemplating her own future in Mystic Falls.

The crossover continues on The Originals S03E14 A Streetcar Named Desire (II).

While Stefan and Valerie search for a magical herb that can keep him hidden from Rayna, Damon comes up with his own plan to take her down for good. However, while at The Armory, Bonnie makes a shocking discovery about Rayna that brings Damon’s plan to a screeching halt.

Elsewhere, a conversation with Caroline leaves Stefan questioning their future together, while Matt decides it may be time to truly take a stand against the vampires of Mystic Falls. Finally, as the season’s middle chapter draws to a close, Damon’s desire to take himself out of the game ramps up as he races to complete unfinished business with Stefan and Bonnie.

In an attempt to make things right with his brother, Damon offers to have Stefan’s scar magically transferred to him, only to discover that doing so may come with some unexpected consequences. With time running out and Rayna closing in on Stefan, Valerie desperately attempts to reason with Damon before it’s too late.

Elsewhere, after being framed for breaking Rayna out of The Armory, Enzo attempts to clear his name, but not before a violent run-in with Nora forces him to make an upsetting discovery.

In the aftermath of his brother's fateful decision, Stefan awakens to find himself thrown into a life or death situation with only his basic instincts to rely on. With time working against him, he sets off on a journey of survival while forced to confront a lifetime of irreversible damage Damon has done to their relationship.

Meanwhile, desperate to save his brother, Damon follows an unusual lead he has come across, while Matt sends Valerie to Dallas to enlist Alaric's help in the search for Stefan. Finally, when Rayna discovers the emergence of a new threat, she sets off on her own mission to find Stefan before the others do.

Determined to capture an escaped vampire named Ambrose, who may be the key to getting Stefan back safely, Damon heads to Memphis with Alaric in tow. However, reluctant to step back into his former vampire hunting ways, Alaric makes his unwillingness to participate clear, while revealing the truth about the past three Damon-less years of his life.

Meanwhile, in the psych ward, Bonnie meets a young woman named Virginia, who provides her with some valuable information about why The Armory may be after her. Finally, Enzo takes matters into his own hands when he learns some devastating news from Rayna.

When Enzo’s efforts to protect Bonnie end up putting her life in jeopardy, they learn that Rayna may hold the key to her survival. With time running out and Rayna at the reins, Enzo and Bonnie reluctantly team up with Damon, who is desperate to save Bonnie’s life and to repair their broken friendship.

Elsewhere, when Stefan travels to Dallas and comes face to face with Alaric, tensions escalate and they are forced to confront the fallout from Stefan’s absence in Caroline’s life. Finally, Enzo learns The Armory’s true motives behind their search for Bonnie.

With Bonnie's life at stake and an uphill battle ahead of them, Damon and Enzo lead the charge to save Bonnie before her condition worsens. Stefan reluctantly teams up with Matt for the sake of Bonnie and uncovers the truth behind Matt's anger towards him.

Elsewhere, determined to help her best friend, Caroline joins Alaric on a mission and quickly realizes how much she's missed her former supernatural lifestyle. Finally, after their plan takes an unexpected turn, Damon makes a fateful decision that will forever change his relationship with Bonnie.