Damon, Bonnie and Alaric have been spending the summer in Europe to get over their grief while Stefan, Caroline and Matt make a deal with Lily and her Heretics when they failed to defeat them. Caroline and Bonnie miss Elena deeply and each day are writing in a diary of everything that occurs so that when Elena wakes up it’ll be like she never missed anything. Stefan and Caroline evacuate the whole town to protect them from the Heretics but agree that anyone who passes the border will be Heretics' blood meal. Alaric consults psychics about his dead wife. Damon rescues Bonnie from a car accident but only at the last minute. When the trio get back in town, they discover about the deal with the Heretics. Damon and Bonnie make their own plan and kill a Heretic. When Lily learns about the death, she attains revenge by kidnapping Caroline with the help of Enzo.

In present day, Caroline is held prisoner by vervain soaked ropes but escapes from Enzo, only to get recaptured by the Heretic girls. The girls torture her. Valerie seems to be good to her by putting a spell on her which keeps her away from other vampires. Damon and Stefan rescue Caroline from the house which was made easy to enter by making Matt's heart stop temporarily, as Matt was made owner of the house. In the last minute, Stefan is pulled out of the house and Damon is told by Enzo that the Heretics have Elena. Lily and the Heretics perform a funeral ritual for their fellow dead heretic and the love of Lily's life. Lily threatens Damon into admitting to the murder of the Heretic and tells him to keep away from Mystic Falls. Meanwhile, Alaric tests the Phoenix stone on a corpse in the morgue.

Damon sets off on a road trip with Bonnie and Alaric in search of leverage they can use against his mother. The trio searches for and meet the last heretic, Oscar, who defected from Lily's group. Damon asked for Oscar's help in siphoning magic from Bonnie who was getting horrible visions after touching the Phoenix Stone. Oscar refuses to help when he finds out about the stone, and tries to escape by knocking Alaric and Bonnie unconscious and breaking Damon's neck. The trio captures Oscar and makes a deal with Lily in exchange for Elena's coffin. Meanwhile, Caroline, still being held hostage by the Heretics, learns some information about Valerie's past. Flashbacks to 1863 show Valerie meeting Stefan for the first time and showing how they fell in love. In actual fact, Valerie was sent by Lily to watch out for her son but they fell in love. When Valerie planned to run away while pregnant, Julian beat her and brought her back to the ship. There, Valerie killed herself which turned her into the very first heretic as she had died with Lily's blood in her system. At the same time, Stefan learns a few unexpected details about his own past from Lily about how she first met Valerie. Also, Alaric turns to Bonnie for her help after coming clean that he has the Phoenix Stone which can bring the dead back to life. Lily sets Caroline free out of admiration for Stefan's honesty with her.

On Halloween, Stefan and Damon desperately hide Oscar's corpse, as his death disables their exchange plan with Lily, who released Caroline to Enzo's delighted relief. They turn for his resuscitation to Bonnie and Alaric, who admits having kept the Phoenix stone. However the sorcery ritual proves hard to crack while the heretic girls, Nora and Mary Louise come searching for the corpse, which is hid in the dorm. Lily instructs Nora and Mary Louise to kill a student at Whitmore College every hour unless Oscar is returned to her. So, Stefan and Caroline team up to lure Nora and Mary Louise to Whitmore's annual Heaven and Hell dance to keep an eye on the couple while Damon, Bonnie and Alaric try to resurrect Oscar using the Phoenix Stone. Also, Valerie confides in Enzo about killing Oscar in order to prevent him from detailing the whereabouts of Lily's former lover, Julian, whom Valerie has a past with.

Damon and Stefan team up with Valerie, who is searching for Julian's coffin to destroy it. Meanwhile, Rick is dealing with Jo to cope things after she becomes alive again. Bonnie goes to the Salvatore manor to ask Oscar, who is under Enzo's watch, about the Phoenix stone but unfortunately, gets attacked by him. Enzo gets the Phoenix stone as Bonnie loses it when she tries to run away from Oscar. Enzo then stabs Oscar when he goes crazy. When the Salvatore brothers and Valerie reach their location, she explains that the Phoenix stone does not bring people alive but it transferred vampire souls imprisoned in the stone into a body. Just as Valerie tries to burn Julian's corpse, Lily and the Heretics arrive and rescue him. Valerie, who for her actions are left alone by the Heretics, tells Damon that it was Lily's plan to make Elena sleep as long as Bonnie is alive. Damon tries to murder Lily but they escape by making coffins explode and injuring Stefan, Damon and Valerie. Back in the Salvatore house, Enzo, in possession of Phoenix stone, makes Lily choose between him and Julian but Lily chooses the latter and disappointed, Enzo gives her the stone. With the stone, the Heretics revive Julian. Bonnie sadly informs Rick about the stone and that Jo's body might not have his wife's soul. Bonnie is joined by Damon who vows to get revenge on Lily who destroys everything that makes him happy.

Lily and the Heretics throw a party at Salvatore manor which Stefan and Damon also attend. Bonnie arrives with Enzo and she tries to make Lily jealous for Enzo. Meanwhile, Rick deals with Jo and her suddenly declining health. Valerie and Caroline arrive there, where Valerie explains that Jo was human and the vampire soul is not compatible with her body which meant that she was as good as dead. Back in the manor, Julian and the Salvatore brothers get into an argument which brings them to fight until Lily intervenes and says she will never let her children suffer. Rick has to let go of Jo but Valerie finds out the twins are still alive. They then make a locator spell which seems to points nowhere but shockingly Valerie deduces that the twins are inside Caroline's body.

In order to get through to Lily about Julian's manipulating ways, Stefan and Damon confront their mother with painful memories from their childhood. However, when Lily reveals a dark secret she's been harboring for over 160 years, Stefan and Damon are left questioning everything they've ever known about their family. Determined to prove himself to Lily, Enzo comes face to face with Julian and challenges him to a duel, but an unexpected twist threatens to complicate things. Elsewhere, Matt finds himself in the middle of a deepening mystery involving the residents of Mystic Falls, and Caroline's world is turned upside down when Valerie reveals some life-changing news to her.

Lily, Damon and Stefan plan killing Julian which requires unlinking him from Lily with the help of the Heretics. Caroline informs Stefan about her pregnancy who finally comes to terms with it. Enzo warns Lily of the impending threat to her life and they share a moment. Later, Enzo is kidnapped by Matt and his troop. Valerie and the Salvatore brothers corner Julian but are interrupted by Mary Louise. Julian forces Lily to choose between killing Valerie or Damon. Unaware that the unlinking's already done, Lily stakes herself, thinking this could kill Julian. Nora breaks up with Mary Louise as the latter sided with Julian instead of Lily. Everybody then says their goodbyes to Lily before her death, except Damon, who coldly dismisses her for Elena's sleep spell.

Lily is put to rest. Stefan and Damon's search for Julian leads them to a bar outside of Mystic Falls filled with dead Santas. As Julian arrives with his minions, the two parties tiff up which later aggravates back home. Nora and Bonnie become friends during a toy drive. Caroline is struggling with her pregnancy as her feeding urges keep her on the edge; she visits her mom's grave for some peace. The fight between the Salvatore brothers and Julian finally leads to him staking Damon with the Phoenix sword, ergo trapping his soul inside the Phoenix hell-stone. It is shown that Damon is back to his Civil War days, injured and scared. When Nora learns that all this time Bonnie was simply stalling her from saving Mary Louise, she siphons out Bonnie's magic and stakes Stefan with the Phoenix Sword as well.

Damon saves Matt and Bonnie as Caroline stealthily injects him with vervain. Stefan is having disturbing post-hell hallucinations of him and Damon underwater with the latter drowning. In his hallucinations, Damon even posed a threat to his and Caroline's relationship. (Damon kept Stefan from escaping hell-world, so in order to escape, the latter had to let go of him). Soon, Henry's spirit starts haunting Damon. Tyler shows up for Caroline's baby shower. Under Julian's leadership, Mystic Falls is now a shoddy home to his vampire mates. It is revealed that Alaric will move to Dallas and Caroline finds it hard to accept that she has to eventually part with the twins. Matt is arrested by a lady cop named Penny for DUI who later questions his wooden weapons. Nora and Bonnie anxiously plan to face a ruthless legendary vampire huntress (she hunts down any Phoenix sword-staked vampire) after Nora receives an X-marked envelope warning of her arrival. Damon meets up with an apprehensive Tyler forcing him to take him to see Elena. As Damon opens Elena's coffin, he finds Henry. He charges at a prepared Tyler but eventually bashes him against concrete. Henry here advises Damon to attain liberation by letting go of what holds back his true monstrous nature. An exasperated Damon attempts to finish off Henry by setting the coffin on fire. As he watches it burn, Henry reappears telling him that he burnt Elena for good which leaves him devastated. Back home, Stefan assures Damon that he will always have his back who is at a loss of words, unable to reveal that his reason to breathe and live is no more as he killed Elena.

Back in Whitmore, Caroline's supernatural pregnancy is affecting her as the babies are siphoners who keep siphoning away her vampirism magic causing her to desiccate inside out. Valerie tries swapping their magic source for a magic-filled talisman but eventually it all goes in vain. Officer Penny learns about Mystic Falls brimming with vampires from Matt. Bonnie, Mary Lou and Nora search for Rayna Cruz, "The Huntress" finding her old and feeble in a psychiatric ward. Puzzled, the Heretics carry on their search when suddenly, Rayna attacks Bonnie who is saved just in time by Enzo who kills off Rayna. It is revealed that Enzo sent the 'X' cards to track Rayna; he burns her to ashes only to revive her back in her young true self. Elsewhere, Damon returns to his road-kill antics, picks on Julian and indulges in dangerous games with his mates. The fight gets nastier with Julian stepping up to fight him. By this time, Stefan has reached the spot and begs Damon to stop, who gives him a deaf ear continuing to fight as if he had a death wish. After a while, Damon begs Julian for death. Stefan interferes and finally gets Damon to walk off the ring. Eventually, Damon discloses about him burning Elena alive to a stunned Stefan who beats him up, abandons him and has a breakdown. He is now hell bent on killing Julian. Damon looks on as he stands there taken over by remorse and bleeding profusely. Back in Mystic Falls, Valerie and Stefan finally take on Julian as Stefan catches him off guard and stakes him while Valerie keeps them cloaked. Back in Salvatore boarding house, Damon gets an unexpected visitor, a brunette (she saved him during one of the ring fights) who comes in and kisses him. Wallowing in emptiness, Damon gazes into her eyes accepting the bitter truth of fate and as a final jolt of mental agony, he bends down to kiss her back.

Rayna is a supernaturally blessed vampire huntress who was once compelled by Julian to kill her own father, a hunter belonging to one among The Five, using the Phoenix sword as her weapon. Back in 1903, hell bent on seeking revenge, she had impaled Beau and staked Julian into the Phoenix hell-stone. She has now released herself and retrieved her sword from Bonnie and Damon. Caroline's fast desiccation called for an early C section delivery which was aided by all the Heretics and later Bonnie. Suddenly, Beau's wound reopens and he gets killed and burnt by Rayna. Nora and Mary Louise run for their lives. Meanwhile, Valerie and Stefan try easing the delivery (the twins were reluctant to come out thus leave their constant source of magic). Bonnie, Alaric and Valerie watched as Caroline successfully gave birth to the twins. Damon distracted and tried fighting Rayna but almost gets staked just as Stefan came to rescue. In this process Stefan gets marked by the sword once more forcing him to run from her. Enzo informs Damon that Elena is alive and well protected by his men and that he was hallucinating her death. Beyond relieved, Damon promises Stefan that he will make things right now that life has offered him a second chance. Alaric names the twins Josie in honor of their mom Josette Laughlin, and Elizabeth, in honor of Caroline's mom.

Caroline moves to Dallas with Alaric and the twins. Valerie locates an anti-magic bar in New Orleans, "St. James Infirmary" where Stefan must hide (as Rayna's sword will not be able to trace him there). At the bar, Stefan meets Klaus. He eventually finds out that Stefan is there hiding from Rayna and is furious. He asks Stefan to leave, and Stefan forgets his phone. Klaus gets to talk with Caroline, finally agreeing to protect Stefan and does so. While on the run, both Nora and Mary Louise are tranquilized and captured by men who work for "The Armory". Meanwhile, Bonnie and Damon meet Enzo at a supernatural museum-like organization named "The Armory", who are desperate to lock up Rayna. Enzo works for them as they are giving him information about his family. He wants to know Stefan's location in order to lure Rayna in. Damon adamantly keeps his brother's location a secret after getting warned about the organization's dubious past from Valerie. An equally adamant Enzo tranquilizes Damon and knocks out Bonnie (it is shown that, somehow, Enzo makes Bonnie immune to magic). Damon finds himself locked in with a comatose Tyler who will soon transition into a werewolf because it is a full moon. Bonnie takes desperate measures to save Damon from being bitten. Damon struggles with Tyler, who makes him realize that "people around him are always dying in order to save him and it must stop". Taking it to heart, Damon advises Bonnie to not open the cell as she could die. Undeterred, Bonnie manages to open the cell, only to get her skull bashed by Tyler who runs away after a fight. Damon sees that she is not healing with his blood and gets her hospitalized. As he talks to an unconscious Bonnie, he says that he is deeply hurt to have put her and Stefan's lives in danger, both of whom tried to save him. This makes him think that it would be best to take himself out of the equation as to no longer bother his loved ones, and it will all end tomorrow.

This episode begins a crossover with The Originals that concludes on "A Streetcar Named Desire".

Stefan and Valerie pursue a herb that can hide them from Rayna. With help from Matt, Damon finally captures Rayna and kills her multiple times in order to die permanently. Bonnie and Enzo discover that once Rayna's lives are over, all of those she marked will die as well and inform Damon just in time before she dies permanently. Damon escapes and notifies Stefan of his intention to desiccate for the next 60 years, to Stefan's disapproval. After an advice from Penny, Matt confronts Stefan and tells him and all vampires to get away from Mystic Falls, otherwise he will show the world the existence of vampires on a CCTV footage. Damon arrives at the storage unit where he plans to desiccate alongside Elena's coffin, but Bonnie shows up letting him know that she is extremely hurt with his decision. She leaves him there and Damon finally lies down to slowly desiccate near to death with hopes that he has saved his loved ones from the array of bad choices he makes putting their lives in jeopardy.

Enzo, Damon, Stefan and Caroline try coming up with plans to open The Armory while Matt and Bonnie are chasing after them. While doing so, they meet an accident that injures Matt badly. Alaric and Caroline decide on making the twins open up the Armory by siphoning off Bonnie's spell. Penny's spirit makes Matt realize that he deserves better, making him regain his consciousness. The twins open the Armory. Damon and Stefan go inside. Enzo lures Bonnie to the cabin letting Damon and Stefan buy more time. The tiny cabin gets nasty as Bonnie, unable to hold her urges, holds a stake down Enzo's chest. While searching, Damon and Stefan finally approach the vault which Damon decides to venture in, alone. He assures Stefan that in some way or another, everything will be okay. They share a handshake and hug and part ways as Damon finally gets inside the vault. Enzo recollects of the glorious 3 years as he struggles to the impale while Damon, just in time, finds the Everlasting's body, sets it on fire thus severing the link and lifting the curse off of Bonnie. Outside, Alaric tells Caroline to stay back with Stefan and parts ways on good terms saying that no matter what, they will always be family. Stefan and Caroline get back together. A rejoiced Bonnie forgives Damon on the phone and while he's getting out, he starts hearing Elena's voice. Enzo and Bonnie warn Damon that it is the vault playing tricks with his mind but he keeps following the voice and something scary overpowers him. Enzo rushes in to help encounter the damaged Damon. The monster takes Enzo as well.