Stefan is forced to make a frightening decision. Matt is hopeful that his mom, Kelly (Melinda Clarke) will stay. And, after Caroline's car breaks down in a storm, she makes a horrific discovery that shocks everyone on town
Elena puts herself in a dangerous position as she searches for the truth about Katherine's past and what her own future may hold. Knowing that Stefan would never agree to her plan, Elena swears Caroline to secrecy. Damon uses a new-found confidant to help him try to discover the real purpose and power of the moonstone. Jeremy and Bonnie meet Luka, a new student with a surprising family history.
Elena decides to take matters into her own hands and offers a tempting incentive to Rose for her help. When things take an unexpected turn, however, Rose calls on Damon to deal with the plan Elena has set in motion. Jeremy's reckless attempt to help Bonnie retrieve the moonstone lands him in a life-threatening position and forces Stefan to put himself in danger. Bonnie and Luka form a closer connection. Tyler shows Caroline the Lockwood cellar, where she makes a discovery that leaves them both terrified.
The Salvatore brothers are unpleasantly surprised that killing Elijah didn't harm, but instead released Katherine. Damon indignantly rejects her flirtation. Dr. Jonas Martin uses invisible astral projection to enable his son Luka to retrieve the ash dagger and thus revive Elijah, but Damon notices and fights back and thus kills the invisible Luka. Grieved, Jonas attacks Jeremy, Bonnie, Caroline and Elena, but ends up dead and surprisingly restores Bonnie's powers. Alaric refuses to keep lying to Jenna, who refuses to be protected by secrecy, so they stop dating until the truth can be told. Matt confronts Caroline who ultimately convinces him of her love, and later discloses of being a vampire and has to heal him after a lethal attack.
Jeremy is delighted to have Bonnie restored to her powers, yet worried when accompanying her and Damon to the house where a 100 witches were burned to gather enough power to undo the moonstone's curse. Elena's mother Isobel Flemming's return startles her and even Katherine, as turns out doing Klaus's bidding for a gruesome 'prize'. John Gilbert confesses more wrong choices, also at Jenna's expense, yet unlike furious Alaric, Elena ends up choosing to keep her father in her life. The Salvatore brothers piece together from the Gilbert diaries what they believe equals a secret weapon. Matt can't handle the vampire truth and gets Caroline to wipe his memory.
Original vampire Klaus forces captured Katherine to torture herself. Meanwhile Klaus takes henchman witch Maddox's advice to possess Alaric's body and use his history teacher job as cover to work on the school-kids and attend the high-school 1960s theme dance, where he hopes to tempt Bonnie to overexert her hundredfold witch powers against an unbreakable charm until she dies. Jeremy mistrusts Bonnie's assurance she can cope and consults Damon, who doesn't even confide in Stefan, to brilliantly mount an elaborate trap. Matt teams up with the sheriff for Caroline's sake.
Resuscitated by Elena, who even hands him the dagger as proof of alliance, Elijah explain to her how his Bulgarian family became the first, still most powerful vampires, but witches prevented them becoming invulnerable. He loved Niklaus 'Klaus', being his brother, but has to turn against him in the end. They ingeniously staged the moon curse in order to get vampires and werewolves to help look for a cure for Klaus's real curse, doubly monstrous genes. Alari-Klaus toys further with Katherina and instruct Maddocks to fetch a new body so he can leave Rick's. Stefan bickers with Damon over how to protect Elena, who shocked both of them but also prevents a fraternal fallout.
Klaus completes his preparations to break the moon curse but luring Tyler home to visit his mother after a non-accidental fall. The Salvatore brothers bicker worse then ever over how to protect Elena, who wants to take risks by doing things Elijah's way, which will kill her but relies on an ancient resuscitation elixir. Stefano takes her away on a 'last day' excursion. Matt finds helping the sheriff with Caroline about unbearable. Alaric's secret is finally discovered by Jenna, who takes it well but runs into tragic trouble. Klaus refuses to wait until the next full moon and unveils he even has a full backup plan. Tyler can't control his metamorphosis until he's safely locked into the tomb.
Damon sees the bite on his arm with the growing wound. Meanwhile Matt shoots Tyler and then he tells to Caroline that neither her mother nor he is compelled and they know that she is a vampire. Jenna finds that she is a vampire; Greta completes her transformation and Klaus brings Jules and kills her. Damon tells Stefan that Klaus transformed Jenna into a vampire and John returns and meets Damon. Jeremy and Bonnie study the journals and the grimoire to see if they can save Elena. Stefan offers himself as the substitute for Jenna. Caroline brings Tyler home and Matt breaks up with her. Elijah promises to kill Klaus while John plots a deadly plan to save Elena from the transformation. Klaus does not accept Stefan and kills Jenna. However, during his transition, Bonnie uses her powers and Elijah comes to kill his brother in the name of their family.
Damon asks Elena to forgive him for forcing her to drink his blood but she does not accept his apologies. Soon Damon is raving and he has daydreams with his life with Katherine in the past and Elena in the present. Stefan tells Elena Damon's condition and she decides to seek him out. Stefan meets Bonnie and discovers that Klaus might save his brother and he looks for Klaus. Meanwhile Jeremy finds Damon and brings him to the Grill; however Sheriff Forbes shoots Damon but hits Jeremy instead and he dies. Alaric brings Jeremy's body and Bonnie tries to resurrect him using her witch powers, but there is a side effect. Stefan meets Katherine in the apartment and out of the blue, Klaus arrive with Elijah. Stefan learns that Klaus's blood can save his brother and he accepts the horrible condition imposed by Klaus to save his brother.
Klaus takes Stefan to Chicago, where he wants to resuscitate his sister Rebekah, who might hold the key to breaking the curse. Gradually, Stefan is reminded of his Prohibition period affair with her her while still bloodthirsty himself, and its tragic end. Tyler is rightly worried, turning for an ally to her mother sheriff Forbes, about the whereabouts of Caroline, whose bully father Bill actually holds her in a dungeon for 'vampire aversion therapy' of the most flagrant kind. Katherine puts Damon on feared Klaus's trail, so he can mount a rescue with Elena after putting her in her place.
In Chicago, Katherine meets Stefan in front of a store and she tells that Elena has the necklace that belongs to Rebekah. She also feels that Stefan is plotting a scheme against Klaus, but he does not share his plan with her. Meanwhile, in Mystic Falls, Anna shows up to Jeremy and talks to him that she is alone in the afterlife. Gloria seeks out the necklace using a spell while Bonnie and Caroline visit Elena; out of the blue, her necklace burns her chest. Damon is upset with people trying to change him to be Mr. Nice Guy. Sheriff Forbes asks him to compel Bill to forget everything but Bill resists. When Damon decides to kill Bill, Caroline protects her father. Meanwhile Gloria tortures Stefan to discover who is wearing the necklace but Katherine unexpectedly kills the witch. Stephan discovers that Klaus fears a vampire hunter, Mikael, and tries to get more information from Rebekah. She suspects of his attitude and tells to Klaus that decides to return to Mystic Falls.
Despite all that has happened, Caroline is determined to see that Elena, Bonnie, Matt and Tyler all enjoy a traditional Senior Prank Night before the school year begins at Mystic Falls High School. However, when uninvited guests show up, it doesn't take long for the evening to take a deadly turn. Damon convinces Jeremy that he can use his new connection to the other side to help find a way to defeat Klaus. Finally, Klaus deepens his hold on Stefan and uses him for increasingly violent and dangerous purposes.
Elena meets Stephan at the high school and he tells that he is watching her following Klaus's order. Rebekah, who is staying at the Salvatore's house, is in the same class as Elena. Elena plots with Alaric and Damon to lock Stephan in the dungeon of the Salvatore house. Tyler is fascinated and reveling in his sire bond to Klaus. Vicky convinces Matt to bring her back from the dead. Anna tells to Jeremy that darkness is surrounding Vicky, and that she has made a pact with an original witch. Vicky hits Matt on the head and seeks out Elena as part of her agreement with the witch. Meanwhile, Damon stays with Rebekah while Elena and Alaric abduct Stephan. Katherine awakens Mikael and he confesses that he does not drink human blood, he drinks vampire blood.
On the day of the Night of the Illumination in Mystic Falls, Mason ties Damon to a chair and the vampire believes that it is a prank of his brother Stephan. Later Mason tells that he is seeking redemption and wants to destroy Klaus to help Tyler. He goes with Damon to a cave with tunnels where it is supposed to have a weapon to destroy the Original Vampire. Elena asks Jeremy whether he may contact Lexi to learn how she can bring humanity back to Stephan, but her brother explains that he has no connection with Lexi. Bonnie goes with Caroline to the place where the witches were burnt and she casts a spell from the Grimoire to bring the dead back. Her grandmother Sheila returns and tells that she must close the passage, destroying the necklace, since the Original Witch is sending every ghost that still has pending business back to Mystic Falls. Meanwhile, the vampires from the tomb also return seeking revenge. Lexi contacts Elena and she starts Stephan's "treatment". Caroline does not find the necklace on the place that Damon told her that it would be and she suspects that Anna has stolen it. Damon can not go ahead through the tunnel that is protected and Mason goes alone. Anna returns the necklace to Jeremy and Bonnie casts a spell; Lexi, Mason, Anna and her mother, the vampires from the tomb and Sheila vanishes.
Damon, Alaric and Elena reach a hidden cage in the secret tunnel beneath the Lockwood mansion. Alaric studies the runes and primitive pictures, which indicate it was the home of an ancient Viking family, who interacted with the first werewolf, vampire and witch. They confront Rebekah, who is shocked to tie it up with her memories of their youth, when their father Mikael, now the only hunter they truly dread, bullied his sons, especially Niklaus, leading in interaction with the originally friendly werewolf neighbors to family drama and the origin of vampires. Adter taunting Stefano, Damon releases him from Lexie's 'aversion therapy' and take shim along to seek Mikael's help. Alaric and Elena work out that Rekebah's memories don't take account of a last, crucial cruel twist.
The homecoming dance becomes the backdrop for a battle of lethal wits between Damon's party, including Mikael and Rebeka although not at all reconciled, and Klaus's, which fields the hybrids by diverting the party to the Lockwood mansion. Tyler surprises Caroline by stating he doesn't really mind being under Klaus's spell as hybrid, it's not worse then monthly lunatic agony as pure werewolf. Fearing even with the eternal oak stake in Mikael's hand Klaus may outsmart them, Damon secretly enlisted Katherine, but Klaus prepared the most stunning surprise.
Bonnie has weird dreams with four coffins. Jeremy hangs around with Tyler and invites him in his house. Stephan meets Bonnie and asks her to hide the coffins of Klaus's family. Klaus tries to force Damon and Elena to seek out Stephan and compels Jeremy to stand up in front of a pick-up driven by a hybrid in high speed without his ring; however Alaric saves him but has difficulties to recover. Jeremy kills the hybrid and he takes Alaric to the hospital with Elena. Damon meets Stephan and he tells that he saved Klaus to save Damon's life. Then Damon asks to participate in Stephan's plan against Klaus. Stephan accepts provided Elena does not know the plan. Elena makes a deal with Klaus and delivers Rebekah to him. Then she asks Damon to compel his brother to leave Mystic Falls.
Bonnie tries to open the coffin and overhears something, but Damon and Stephan arrive in the house and Damon kills the hybrid. Elena and Bonnie are preparing a birthday party for Caroline at school and Jeremy says goodbye for them. Tyler meets Caroline to tell that he would never hurt her since he loves her, but Klaus controls him. Stephan threatens Klaus and asks him to send his hybrids out of Mystic Falls and beheads one hybrid in front of Klaus to prove that he is not kidding. Klaus summons Tyler and compels him to bite Caroline, but Tyler reacts telling that he will not hurt Caroline. When Caroline arrives home, Elena, Bonnie and Matt are waiting for her; however they go to a tomb to celebrate her funeral instead. Out of the blue, Tyler appears and bites Caroline on the neck. Damon and Alaric go to a counsel meeting to raise fund to rebuild a bridge and Damon meets Klaus that tells that Stephan must stop beheading his hybrids. Meanwhile Alaric flirts with Dr. Meredith Fell and protects her against her ex-boyfriend and coroner Dr. Brian Walters. Damon unsuccessfully tries to stop Stephan from killing hybrids. Stephan abducts Elena, calls Klaus, gives her blood to her and promises to kill her, driving his car in high-speed. Klaus agrees to send the hybrids away. Klaus goes to Caroline's home and gives his blood to Caroline and saves her. Damon brings Elena home and on the next morning Jeremy travels to Denver. Alaric meets Dr. Fell while Sheriff Forbes finds Brian murdered.
Prophetic dreams about the mysterious fourth coffin lead Bonnie and Elena to a surprising source, while Tyler seeks help to break free from Klaus' bond so he can be with Caroline. Alaric's new friend Dr. Fell has a secret no one sees coming, and Stefan's interference in Elena's life reveals something that surprises even him.
Now Klaus has Elijah back, they host a dinner party to negotiate a future with the Salvatore brothers, who actually procrastinate. Meanwhile combined witchcraft finally opens the mystery coffin, from which a scary surprise guest is released, but both families will be shocked. Alaric has been wounded dangerously by lover Dr. Fell, who happens to be supernatural, which makes saving him problematic, but Elena steps up. Caroline's father Bill Forbes refuses to survive his vampire bite by allowing Caroline to turn him into one like her.
Now Klaus's original family's coffins are open, he's supplanted as family head by their sorceress-maker, mother Esther, who holds a grand ball in their splendidly restored mansion. Invitations with gifts and where needed other persuades go to the Salavtore brothers, Alaric, Matt, Caroline and especially Elena, who is asked for a private meeting. After Stefan prevents Damon from stopping her, she learns that Esther, aided by son Finn, needs Doppleganger blood to put a fatal spell on her children, the others being an 'abomination' except Elijah, firstly binding their fate. Tyler prepares his return.
After starting her day with a startling discovery of Damons' latest indiscretion, Elena is frustrated to find that none of her friends agree with her on how they should react to the Original family's internal power struggle. Once again caught up in the destiny of the Bennett witches, Bonnie and Abby find themselves playing a part in a ritual to appease the spirits of nature. When Elijah gives Damon and Stefan a dangerous ultimatum that puts Elena in danger, they turn to Alaric and Meredith for help with a plan that leads them to a terrible choice.
Stefan still struggles desperately to get his blood-lust back under control. Damon keeps an eye on him, but has other priorities. Damon's former teacher Sage returns as his lover, in a secret pact against Rebekah, whom he seduces to keep an eye on her quest for the original white oak's sole known shoot. The old vampires are actually in league and torch the bridge made from its wood, fearing the weapon that could be made from it, but Damon stayed a step ahead. Dr. Fell tries to treat Alaric medically while Bonnie attempts to undo the curse which caused his hereditary madness, but the they aren't careful enough, so Damon must intervene. Jeremy calls home from Denver, telling he only suffers from melancholy but does well at school.
Jeremy is furious when Klaus tries to control him by putting Matt's life in danger. Damon coaches Jeremy as he prepares to take on Klaus' new vampires, but they find that Kol has beaten them to it. Kol makes it clear that he will stop at nothing to convince everyone to give up the search for the cure. Looking for a new ally, Rebekah reminds Stefan that they were once close friends. When Sheriff Forbes and Mayor Hopkins question Shane about his involvement in the Founders' Council deaths, Bonnie steps in with questions of her own, and Shane's responses push Bonnie to the edge of her powers. Elena negotiates with Klaus to keep Jeremy safe, but when danger suddenly appears from a totally unexpected enemy, Elena comes up with her own daring plan for Jeremy.
When Elena and Katherine have the same dream that Stefan is in danger and desperately needs their help, they convince Damon to help them find Stefan. However, their plans are thwarted by a mysterious young woman named Tessa who seems to know everything about Stefan's history. In flashbacks to a distant time and place, Tessa reveals the shocking secrets in her past and what she has planned for the future. She also has a disturbing message for Damon about his own future. Silas forces an unwilling accomplice to help him search for Katherine, leading to a confusing and life-threatening situation for Matt. Finally, Silas reveals the reason he's determined to find Katherine, and Damon and Elena face a disturbing new reality.
On campus, Elena is touched by a sad and secretive student named Aaron. Elena and Damon attend the Whitmore Historical Ball dressed as Anne Boleyn and Henry VIII. At the ball, Elena shares a dance with Dr. Maxfield, who has a disturbing message for her. Caroline's evening at the ball takes her from happiness to heartbreak. Meanwhile, Nadia reveals her surprising history to Katherine, and Damon tries to make a deal with Silas. But when Silas demands that Damon commit an unthinkable act, it leads to a violent confrontation.
Silas happily announces his new goal to Damon and Elena, but they are skeptical when he promises to accomplish one important task in return for their help. Tessa confidently tells Stefan about her next move, then realizes that Silas has managed to outsmart her. A desperate Katherine discovers a new and unexpected consequence of becoming human again, and realizes she needs a new place to stay. In exchange for a spot in the dorm room, she offers to show Caroline how to get answers from Dr. Maxfield. Bonnie is touched by Jeremy's strength and determination to stand by her. Finally, Damon is stunned when he figures out the secret to Tessa's plan.
The power of doppelgangers.... While Elena and Damon try to explain Amara's situation to Stefan, Dr. Wes Maxfield gives Katherine some deeply disturbing news. Nadia shows up at Caroline's dorm room searching for Katherine. After a surprising conversation with Amara, Jeremy and Bonnie share a glimmer of hope. Silas fails to keep a promise, causing Damon to turn to Tessa for help with his new plan, and Stefan makes a heartbreaking confession to Damon and Elena.
At Whitmore College, Elena and Caroline decide it's time to throw a big party, but their plans are interrupted when Jesse suddenly needs Caroline's help. At Elena's request, Damon comes up with an effective method to get Wes to answer his questions. At the party, Elena finds that she and Aaron have a lot in common, and Caroline grows more concerned about Jesse. Meanwhile, Katherine does a favor for Matt and manages to get through to Stefan, who is still struggling to overcome the events of the summer. Finally, Bonnie does her best to cope with her new reality, and Damon makes a terrifying discovery about a secret society.
Damon realizes Elena is in danger and enlists Stefan's help to find her. The brothers pay a visit to Aaron, and Damon shocks Stefan by revealing his first-hand knowledge of Aaron's family. In an attempt to stop Damon, Dr. Wes unleashes his secret weapon, forcing Damon to deal with a part of his past he thought was gone forever, as well as the consequences of his decades-long plan for revenge. Meanwhile, Elena is horrified by Dr. Wes' confessions about the dark history of Whitmore College and his own ultimate goal. Finally, a frantic Katherine turns to Matt for help, until she realizes that Nadia may be the one who can solve her problem.
Damon tries to get back together with Elena, however, Katherine has a plan and attempts to take Elena's body permanently. Tyler is upset with Caroline and Matt is used by Katherine. Enzo finds Damon and they decide to become a team again.
Hoping to help everyone move past recent traumatic events, Caroline convinces Elena and Bonnie to attend Whitmore College's "Bitter Ball" for broken-hearted students. Bonnie is intrigued with a fellow student named Liv, who appears to be dabbling in witchcraft. Tyler starts to worry about Matt's relationship with Nadia. After making a disturbing discovery, Stefan has a frustrating conversation with Damon and Enzo. Dr. Wes struggles to continue his research project with help from a new benefactor named Sloan. Still bent on revenge, Damon and Enzo resort to violence to convince Bonnie and Jeremy to help them, but their plan takes an unexpected and horrifying turn.
As Damon's behavior escalates from destructive to deadly, Stefan begins to regret their last conversation and decides to track Damon down and intervene. For reasons of her own, Elena volunteers to come along. Dr. Wes enlists the Travelers to set a trap that will once again test Damon's friendship with Enzo. After a heart-to-heart talk with Nadia, Matt enlists Caroline and Tyler's help to protect Elena, leading to a violent confrontation. Later, when Stefan tries to comfort a dejected Caroline, their conversation leads to a horrifying realization.
While Nadia remembers her centuries-long search for her mother, Stefan, Caroline and Matt come up with a desperate new plan to save Elena's life. For the second time, Bonnie and Jeremy must turn to Liv for help. Damon baits Tyler into a nasty confrontation, then takes off to seek revenge on Dr. Wes. Caroline and Tyler come to a new understanding. Finally, Bonnie learns of a terrifying secret that will threaten the lives of all her friends.
When Stefan tries to explain recent events to a very sick Elena, her first instinct is to call Damon. At the same time, Damon is trying to figure out how to make a disturbing confession to Elena. While going through Dr. Wes' files, Caroline discovers a frightening secret, and is surprised when Enzo appears, claiming to have the solution everyone is searching for. At Enzo's insistence, Caroline asks Stefan to meet her at a mysterious location where they are joined by a group of Travelers, including Sloan, who reveals new information on the importance of doppelgangers.
Both Stefan and Elena are suddenly having unsettling dreams of an alternate version of the life they might have had together. Bonnie has a disturbing encounter with Grams, who warns her about frightening changes on the Other Side. Enzo gives Damon unwanted relationship advice, then admits he is searching for a woman he loved decades before while he was held captive by the Augustines. Liv enlists Matt, Jeremy and Tyler to help track the Travelers and keep them from taking control of Mystic Falls. Bonnie is hurt and angry when she learns that Jeremy is working with Liv behind her back. Luke shows up at the Salvatore house and explains what he knows about Markos and the Travelers to Damon, Elena and Enzo. Matt has a terrifying encounter with inhabitants of the Other Side. Finally, when Damon finds Markos, he is both relieved and disturbed by what Markos has to tell him.
Damon and Caroline suspect Stefan and Elena of keeping a secret while they hide from the travelers, unaware of the dead man out for revenge. Meanwhile Matt, Jeremy and Bonnie help Tyler get rid of Julian.
When Stefan and Elena escape from Markos' control, only to find themselves Stranded in a remote location, Stefan gets philosophical with Elena about her relationship with Damon. After their attempt to protect the doppelgangers goes badly, Liv and Luke come up with a dangerous new strategy. Damon recruits Matt and Jeremy to help him set a trap for Markos, who turns out to have a devastating surprise of his own. Bonnie finally admits to Caroline that she's been keeping the truth about the Other Side from everyone. Finally, while Bonnie searches desperately for a way to stop Markos, Caroline is witness to an unthinkable act of violence by one of the Travelers.
Four months have gone by since the Other Side broke down and Bonnie and Damon were lost. Mystic Falls is still a supernatural-free area. Everyone is grieving in their own ways, and some worse than others.
Knowing she needs to come to terms with the loss of Damon, Elena turns to Alaric to help her move on with her life. Enzo convinces Caroline to join him as he tracks down a lead to get Damon and Bonnie back, but Caroline is shocked when they make an unexpected detour and uncover what Stefan has been up to. Meanwhile, Matt worries about Jeremy who is spending time with Sarah, a mysterious girl who has recently arrived in Mystic Falls. Elsewhere, Tripp, leader of the community protection program, makes an interesting confession to Matt about his connection to the town. Lastly, with the Other Side destroyed and gone for good, Damon and Bonnie reluctantly band together to uncover the mystery of where they are and how they are going to get back home.
Elena gets some hopeful news from Alaric and Stefan regarding the Gemini Coven; Tyler tries to help Liv and Luke after learning of disturbing plans the coven has for them; dinner takes a drastic turn for Jo; Kai makes a dangerous discovery.
Bonnie tries to replicate her favorite traditions, while reminiscing about happier times with her friends; Sheriff Forbes brings holiday cheer to Caroline at Whitmore College; Alaric turns to Damon and Elena for help when Jo goes missing; Tyler approaches Liv and Luke with a risky plan; Jeremy helps Matt carry out a plan to take down Enzo; Stefan is forced to break some devastating news to Caroline.
When Liv and Luke's father arrives to town to celebrate their birthday, they try and convince him to let Jo and Kai take their place in the merge ceremony. After Tyler finds out that the merge is happening sooner than he expected, he urges Liv to let him talk to her father. Meanwhile, after Caroline's plan to cure her mother takes an unexpected and devastating turn, Elena, Stefan and Damon gather at the hospital, while Jo attempts to save Sheriff Forbes' life. Lastly, with the merge set to take place, Damon's risky plan quickly sends things spiraling out of control, forcing one of the twins to take matters into their own hands.
In the aftermath of Jo, and Alarics wedding, an unexpected guest shows up, putting Elena's life in jeopardy. Despite Matt's attempt to leave town to save himself, Bonnie takes matters into her own hands after finding herself on the receiving end of a twisted plan...
Damon is faced with a new reality without the love of his life; Bonnie decides to be Damon's moral compass, and look out for Alaric, who lost his fiancé. Stefan protects the town from Lily; Enzo must decide Who he is loyal to.
In the aftermath of a clever plan orchestrated by Lily, Damon sets off on a road trip with Bonnie and Alaric in search of leverage they can use against his mother. Meanwhile, Caroline, who is being held hostage by the Heretics, learns some shocking information about Valerie's past, while Stefan learns a few unexpected details about his own past from Lily. Finally, Alaric turns to Bonnie for her help after coming clean about a secret he's been keeping.
After being reunited with her former love Julian, Lily hosts a dinner party to introduce him to Damon and Stefan and to declare peace between her family of Heretics and the residents of Mystic Falls. Damon and Stefan find themselves at an impasse when they realize they have differing views on how to handle Julian's arrival. At the party, Bonnie and Matt uncover a strange mystery involving some unsuspecting residents, while a devastating revelation causes Alaric to reach his breaking point.
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 years of his life without Damon. 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.
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.
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.
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 (guest star Wole Parks), Stefan (Paul Wesley) is determined to have one thing go right - Christmas Eve with Caroline. However, when Damon (Ian Somerhalder) and Sybil (guest star Nathalie Kelley) crash their Christmas Eve dinner, which had been joined by Alaric (Matt Davis), Matt (Zach Roerig) and Peter (guest star 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.
Stefan and Damon attend an anger management support group looking for their next victim. Sybil is still alive and teaching a group of high school students who she'll later use as leverage to get Caroline to locate a historical artifact that can be used against her. Meanwhile, Stefan and Damon continue their commitment to Cade as they test the morals of a young doctor, Tara.