It is four months since a tragic car accident killed the parents of 17-year-old Elena and her 15-year-old brother, Jeremy. As the school year begins, Elena and her friends are fascinated by a handsome and mysterious new student, Stefan Salvatore.

As Mystic Falls prepares to celebrate the passing of a comet, Vicki is still in the hospital. Stefan goes to the hospital and tries to use his abilities to make sure Vicki doesn't remember what really happened, but his attempt is cut short when Vicki's brother arrives.

Elena tries to ignore Bonnie's warnings about the disturbing vibes she got from Stefan and invites Stefan and Bonnie to dinner. But the evening is disrupted by the unexpected and unwelcome arrival of Damon and Caroline. Plus, the town is shocked by an act of violence.

Elena asks Stefan to escort her to the town's annual Founder's Party. Zach reveals a useful family secret to Stefan. At the party, Damon tells Elena a story about the Salvatore family's past. Finally, Stefan takes action to get Damon out of his life for good.

Stefan is hopeful that his plan to get rid of Damon is working, and decides to reveal parts of his past to Elena. At a fundraising car wash, Bonnie is surprised by powers she didn't know she possessed. Finally, Elena hears a disturbing story about the Salvatore family.

Elena demands that Stefan explain the frightening events that have been happening in Mystic Falls. In flashbacks, Stefan explains how his rivalry with Damon began. Back in the present, Damon impulsively takes control of Vicki's future, and a terrified Vicki runs away.

As Vicki's behaviour becomes more dangerous, Stefan tries to help her. Elena tries to convince Jeremy to stay away from her. Trying to cheer Vicki up, Matt takes her to the high school's haunted house, but the evening soon takes a terrifying turn.

On his birthday, Stefan is surprised by a visit from Lexi, one of his oldest friends. Still upset by the events at the Halloween haunted house, Elena does her best to stay away from Stefan. Plus, Damon's offer to help Sheriff Forbes has sudden and tragic results.

Jeremy gets a break from the mysterious new history teacher, Alaric Saltzman, and introduces Alaric to Jenna. Bonnie is having terrifying dreams about one of her ancestors. Damon finally reveals to Stefan the stunning reason he has returned to Mystic Falls.

When Sheriff Forbes tells Damon there has been another attack, he offers to track down the killer and learns a startling piece of information. Stefan and Elena come to a new understanding, but everything changes when Elena accidently makes a devastating discovery.

Damon takes a trip to Georgia and enlists the help of an old flame to figure out how to open the tomb. In the process, Damon comes face to face with someone who is determined to make him pay. When Damon returns, Stefan is waiting with news that will change their world.

As Stefan and Damon try to figure out the identity of the new vampire in town, Stefan gives Elena jewellery filled with Vervain to protect her family and friends. Damon and Stefan accompany Elena to a school dance, where Alaric introduces himself to Damon.

In flashbacks, Stefan and Damon recall the long-ago actions taken by townspeople. Back in the present, Bonnie's date with Ben takes a frightening turn. Elena helps Stefan as he and Damon race to find the missing journal that belonged to Elena's ancestor. history.

Stefan helps Elena and Bonnie out of a dangerous situation. Jeremy asks Anna to a party in the woods, unaware that she has her own reasons for wanting to meet him there. Stefan, Damon and Elena work with Bonnie and Grams to open the tomb.

Matt and Caroline are surprised by the sudden reappearance of Matt's mother, Kelly. Alaric discovers shocking secrets from his own past. With help from Jenna and Stefan, Elena is determined to find out everything she can about her birth mother.

Anna brings a surprising guest along when she pays a visit to Damon. Elena and Stefan go on an awkward double date with Caroline and Matt. Jenna reunites with her old friend Kelly, and Jeremy's relationship with Anna takes an unexpected direction.

Stefan and Damon make a dangerous enemy and Stefan suddenly finds himself in a perilous situation. Damon and Elena try to convince Alaric to work with them. And, after Caroline's car breaks down in a storm, she makes a horrific discovery that shocks everyone in town.

While Stefan struggles to control his new situation, Elena and Jeremy are surprised by a visit from their uncle, John Gilbert. At a Founder's Day event, Stefan displays a rare party attitude and Damon's attempt to find out why Uncle John has returned takes an ugly turn.

Elena and Caroline compete for the title of "Miss Mystic Falls" against other girls from town. Elena is happy to have Bonnie back in town, but Bonnie still has issues to work through. John Gilbert tries to intimidate Damon, but his plan doesn't have the desired effect.

Both Stefan and Damon reveal parts of their history to Elena, until she finally learns the truth about how they became vampires. Pearl has an ugly confrontation with John Gilbert. Damon and Alaric try to find a mysterious invention before John does.

Isobel returns to town and stuns Alaric with her attitude. When Isobel and Elena finally meet, Isobel refuses to answer most of Elena's questions, but reveals that she will stop at nothing to find the mysterious invention John Gilbert has been searching for.

Founder's Day has finally arrived, and everyone is busy with last-minute preparations for floats and fireworks. Although Damon and Alaric do their best to stop him, John Gilbert sets a plan in motion that brings Founder's Day to an end amid chaos, destruction and death.

Elena arrives home to a nightmare as she discovers the fate of Uncle John and Jeremy. Sheriff Forbes waits to hear if Caroline will survive. Still reeling from his father's death, Tyler is surprised when his uncle, Mason Lockwood, arrives to console the family.

When a confused and desperate Caroline leaves the hospital and joins her friends at the Mystic Falls Carnival, Damon wants to take immediate action. Damon also has suspicions about Tyler's Uncle Mason and attempts to get Mason to reveal his secret.

Elena, Damon and Alaric take a road trip to Duke University and search through Isobel's research on folklore and paranormal phenomena to see if they can uncover any clues to the mystery surrounding the Lockwood family.

Stefan takes drastic measures to find out the real reason Katherine has returned to Mystic Falls, and is shocked when she reveals new secrets about what really happened in 1864. Damon tries a new tactic to resolve his issues with Mason, but it proves costly.

Tyler learns more about the Lockwood family curse from Mason. Elena tries to keep Jeremy from becoming more involved with the Lockwood mystery. Mason gives Sheriff Lockwood some startling information, leading to a night of violence, confession and heartbreak.

Despite Elena's efforts to keep Jeremy safe, he offers to help Damon and Alaric deal with Katherine. Bonnie accidentally discovers new information about Mason and shares it with Stefan, which leads to Damon taking matters into his own hands.

Stefan and Damon decide on a new plan to deal with Katherine at the Lockwood's masquerade ball. Bonnie, Jeremy and Alaric all do what they can to help Stefan and Damon, but Katherine has a surprise planned that none of them could foresee.

Stefan and Damon come to Elena's assistance and, in the process, learn surprising new information about people, vampires and events in the distant past. Jeremy helps Bonnie after she casts a difficult and exhausting spell.

Elena puts herself in a dangerous position as she searches for the truth about Katherine's past and what her own future may hold. Damon uses a newfound confidant to help him try to discover the real purpose and power of the moonstone.

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, Rose calls on Damon to deal with the plan Elena has set in motion.

Caroline helps Tyler prepare for the transformation he is powerless to stop. While Stefan and Katherine play mind games on one another, Damon and Alaric are suspicious when a stranger named Jules shows up in Mystic Falls, searching for her missing friend, Mason.

Stefan has his own ideas about Elena's new plan for the future. While Damon tries to get the truth out of Jules, he asks Elena to keep an eye on Rose, a situation that turns unexpectedly dangerous. Meanwhile, Damon struggles when a life-and-death crisis hits him hard.

Johnathan Gilbert's return to Mystic Falls comes as an unhappy surprise to Elena, Jenna and Damon. Caroline lets Stefan know about her conversation with Tyler, and Stefan does his best to reach out. Plus, a hostage situation soon escalates into a violent confrontation.

Stefan and Elena get away for what they hope will be a romantic weekend at the Gilbert family lake house, not realising that they've been followed. Jules explains the importance of the sun and moon curse to Tyler, but leaves out an important detail.

Stefan tells Elena about a dark time in his past and the surprising person whose influence changed everything. Trying to catch Elijah off-guard, Damon plans a dinner party for him with Jenna, Alaric and Andie, but last-minute information throws Damon's plan into chaos.

Katherine's mind games are getting on everyone's nerves, but Damon, Stefan and Elena realise that her knowledge of Mystic Falls' history will help them stay alive. Alaric makes a surprising confession to Jenna; Katherine makes a different kind of confession to Damon.

Elena and Alaric both lash out at John when Isobel's unexpected arrival leaves Jenna devastated. Bonnie works with Damon and Jeremy to find the spell they'll need to harness her ancestors' power. Plus, Stefan and Damon realise they have a new secret weapon.

As the high school prepares to throw a "1960s Decade Dance", Elena starts receiving disturbing messages from Klaus via an unusual source. Expecting Klaus to show up at the dance, Damon and Alaric attend, but Klaus is playing a complicated game that keeps them on edge.

Stefan and Damon are furious when they discover that Elena has defied them both to make a new ally and take control of the plan to outmanoeuvre Klaus. Flashbacks to 1491 reveal Katherine's introduction to Elijah and Klaus, along with the origin of the moonstone curse.

Damon is willing to go to extraordinary lengths to prevent Elena from being a victim of Klaus's plan to break the curse. Tyler returns to Mystic Falls after receiving a disturbing phone call. The full moon marks the arrival of the sacrifice ritual.

With the arrival of the full moon, Elena tries to prepare for whatever Klaus has planned and Tyler faces his second transformation. Finally, Damon admits the truth to Stefan about a terrible new development they must face.

While Mystic Falls presents a screening of "Gone with The Wind", Damon's memories of Katherine in 1864 mix with the reality of Elena in the present. More than one life hangs in the balance as the consequences of the sacrifice ritual play out to a horrifying conclusion.

On the morning of Elena's 18th birthday, Caroline is busy planning a party, but Elena is focused on searching for any clues that might help her discover where Stefan is. Meanwhile, Klaus and Stefan are busy trailing a werewolf named Ray Sutton.

Klaus puts a plan in motion that will give him even more power, but even with the unwilling participation of werewolf Ray Sutton, things don't go exactly as Klaus had planned. Damon and Alaric reluctantly go along with Elena's new strategy to find Stefan.

Klaus and Stefan arrive in Chicago, where Stefan is reunited with a vampire who hasn't really moved on from her interest in him decades earlier. In a flashback to Chicago in the 1920s, Stefan comes face to face with a shocking chapter from his wild past.

Klaus uses Gloria, a witch he knew long ago, to help him track down missing information that will explain why his plan isn't working. Back in Mystic Falls, a new enemy pushes Damon over the brink and he lashes out in a way that will have lasting consequences.

Senior Prank Night at Mystic Falls High School takes a deadly turn when uninvited guests show up. Damon convinces Jeremy that he can use his new connection to defeat Klaus. Klaus deepens his hold on Stefan and uses him for increasingly violent and dangerous purposes.

On the first day of their senior year, Elena, Caroline, Bonnie and Matt are still reeling from recent events, while Tyler seems to be enjoying everything a little too much. Damon is annoyed by a new houseguest, and everyone is surprised by the arrival of a new student.

As Mystic Falls prepares to celebrate the traditional Illumination Night, the town is invaded by spirits of the dead. After a particularly violent encounter with an angry spirit, Damon asks Bonnie to find the reason behind the ghosts' surprising power.

With help from Elena and Bonnie, Alaric tries to decipher the meaning behind his recent discovery. Elena and Rebekah engage in a mean-girl power struggle, until Rebekah finally reveals some of her family's secrets and the violent past she shares with Klaus and Elijah.

On the night of the Homecoming dance, Rebekah opens up to Elena about why the evening is so important to her. The night takes a surreal turn when Klaus puts his latest plan into action. Determined to outsmart Klaus, Damon enters into a dangerous partnership.

Stefan has hidden the coffins containing the bodies of Klaus' family, and Klaus turns to violence to show no one will be safe until he finds Stefan and gets his family back. After a terrifying incident, Elena and Alaric grow increasingly concerned about Jeremy's safety.

Stefan has hidden the coffins containing the bodies of Klaus' family, and Klaus turns to violence to show no one will be safe until he finds Stefan and gets his family back. After a terrifying incident, Elena and Alaric grow increasingly concerned about Jeremy's safety.

Although Caroline is in no mood to celebrate her birthday, Elena, Bonnie and Matt surprise her with a party in an unusual location. Damon and Stefan disagree on how to handle Klaus, and a reckless Stefan decides to test his theory by taking things to dangerous extremes.

Bonnie believes her recurring dreams about Klaus' coffins will tell her how he can be killed. The dreams also lead Bonnie to a reunion with her mother, Abby, after 15 years. Bonnie's sudden appearance catches Abby off guard, but she does her best to explain the past.

Sheriff Forbes delivers some disturbing news to Alaric and Elena about the weapon used in a recent murder. Klaus hosts a dinner party, where he reveals another story from his family's past. Caroline is heartbroken when she is unable to stop a tragedy from unfolding.

Elena is surprised to receive an invitation to a formal ball being hosted at Klaus' newly renovated mansion. At the elegant party, Elena learns of a horrifying plan that could lead to numerous deaths and she must decide who she can trust with her new information.

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. When Elijah gives Damon and Stefan a dangerous ultimatum that puts Elena in danger, they turn to Alaric and Meredith for help.

The present-day murders in Mystic Falls remind Damon of a similar crime spree a century earlier. In flashbacks to 1912, Damon recalls a beautiful vampire, Sage, who showed him a whole new way to exist. Sheriff Forbes warns Damon not to get involved in her investigation.

A century after their first encounter, Damon and Sage meet again at the ceremony to kick off the restoration of Wickery Bridge. Damon is surprised to learn why Sage has returned, and pleased when she devises an unusual way to help him figure out what Rebekah is up to.

Damon and Stefan focus a new project that will bring them closer to destroying Klaus, and they quickly bring Elena, Caroline and Matt in on the plan. After Klaus threatens someone close to Bonnie, she has no choice but to work on the spell he needs.

Elena and Damon set off together to make sure Jeremy is safe in Denver, and to see if his special abilities can help reveal the information they need about ancient vampire bloodlines. Stefan and Klaus both go to brutal extremes in their search for the missing weapon.

At the school's 1920s Decade Dance, Bonnie asks Jamie to go with her, and Elena asks Stefan. The dance takes a deadly turn when Damon and Stefan realise they need the help of Matt, Jeremy and especially Bonnie to undo a spell that could prove devastating for everyone.

Klaus acts on his intentions to leave town with Elena, but finds resistance from a surprising new enemy. Bonnie calls on Abby to help her with a difficult spell. As events spiral out of control, Elena is determined to protect Caroline.

Determined to protect his sister, Jeremy makes a decision that will change everything. Stefan and Damon leave Mystic Falls together on a mission, but soon split up when Elena needs one of them. Finally, Bonnie makes a secret deal that has heartbreaking consequences.