Just as Damon thinks he's gained the upper hand in his fight against Lily, an unexpected turn of events leaves him scrambling for a plan B.

Vampire hunter Rayna Cruz is on the loose and Damon has to make things right when his actions inadvertently put his loved ones in her path.

Stefan goes to New Orleans to lure Rayna Cruz away from his friends and comes face to face with Klaus Mikaelson, who's suspicious of his old friend's arrival.

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.

When Damon's risky attempt to save Bonnie takes an unexpected turn, the consequences of his actions forces everyone to band together to help her pull through. Meanwhile, when a new threat leaves Caroline's life in jeopardy, Stefan makes a rash decision that ultimately forces them to face the fallout from their relationship. Elsewhere, Enzo tries to hold it together as he painfully watches Bonnie in the fight of her life, while Matt takes matters into his own hands to save one of his closest friends. Alaric also appears.

Despite their best efforts to help Bonnie through the harrowing predicament she now faces, Damon, Enzo and Caroline realize their options are running out and drastic measures need to be taken. With their only chance of saving their friend lying inside the Armory, Stefan breaks the news to Caroline that they may need help from an unlikely source - her and Alaric's twin daughters. Elsewhere, Enzo keeps Bonnie preoccupied by bringing her back to their cabin but when his plan takes an unexpected turn, it'll be up to Damon to make the ultimate sacrifice to save his closest friends. Matt also appears.

Stefan searches tirelessly for Damon and Enzo months after their mysterious disappearance.

No one can accept the loss of Damons humanity that Enzo hopes for too, Damon carelessly tries to prove everyone wrong.

As Enzo continues to fight the control over him, Bonnie finds herself at the center of a deadly game and forced to make a heart wrenching decision involving two of the most important people in her life. At the Armory, Alaric researches a mysterious artifact that he hopes will help in their fight to get Damon and Enzo back. Finally, Damon's downward spiral leads him to Tyler Lockwood who attempts to talk some sense into him before it's too late.

Meanwhile Alaric and Stefan try to find out about the origins of what they are up to, Damon is searching for an artifact so he travels to Texas where he encounters Peter Maxwell who leads him to a new revelation.

Stefan and the others remember what matters most when tragedy strikes close to home.

When her children become the focus of the Siren's latest plan, Caroline (Candice King) takes drastic measures to ensure nothing gets in the way of keeping her family safe. In a race against the clock, Stefan (Paul Wesley) pledges to do everything he can to save the twins, while tensions between Alaric (Matt Davis) and Caroline boil over, leading them to face some harsh realities about the future of their family. Meanwhile, when Enzo (Michael Malarkey) finds himself unable to fight off Sybil's (guest star Nathalie Kelley) latest move, Stefan dives into his subconscious and along the way, sets off a chain of events that leaves him faced with a life-changing decision.

Faced with the fallout from his interaction with Cade (Wolè Parks), Stefan (Paul Wesley) is determined to have one thing go right - Christmas Eve with Caroline. However, when Damon (Ian Somerhalder) and Sybil (Nathalie Kelley) crash their Christmas Eve dinner, which had been joined by Alaric (Matt Davis), Matt (Zach Roerig) and Peter (Joel Gretsch), things quickly take a dark and twisted turn. Meanwhile, in a series of flashbacks to Stefan's past, Cade's attempt to entice him with his mysterious agenda leaves Stefan faced with an unimaginable decision. Kat Graham and Michael Malarkey also star.

Damon and Alaric face an old enemy after finding a weapon that might kill Cade. Stefan is captured by someone from his past. Bonnie tries to reach out to Enzo through Cade.

Damon and Stefan join forces against Cade to protect Elena's casket, while Caroline and Alaric cope with their daughters' growing powers.

A wedding is quickly planned in order for Damon and Stefan to lure a dangerous enemy out into the open.

With the fate of Mystic Falls at stake, Stefan and Damon must fight their greatest enemy for one last battle.