Stefan escorts Elena to the town's Founder's Party. At the party, Damon tells Elena a story about the Salvatore family, leaving Elena with questions Stefan refuses to answer.

Bonnie's abilities surprise Damon. Elena asks Jeremy not to see Vicki. Matt takes Vicki to the high school Halloween dance, but the night takes a terrifying turn.

Recurring guest star Melinda Clarke appears as Kelly, Matt's long-lost mother. Sheriff Forbes (Marguerite Macintrye) asks Damon to be part of a fundraising bachelor auction.

Elena and Caroline compete in a beauty pageant. Spencer Locke appears as one of the contestants. John Gilbert tries to scare Damon

Damon and Alaric try to stop John Gilbert from setting a plan in motion to bring Founder's Day to an end amid chaos, destruction and death.

Elena comes home to a nightmare; Damon realizes Katherine has returned; Tyler receives a surprise visit from his uncle.

When a confused and desperate Caroline leaves the hospital and joins her friends at the Mystic Falls Carnival, Damon wants to take immediate action.

Elena, Damon and Alaric go to Duke University to find Isobel's research into the paranormal and look for clues to the mystery surrounding the Lockwood family; Stefan faces a new danger in the woods; Tyler makes a shocking discovery about Mason.

Tyler learns more about the Lockwood family curse from Mason, and Sheriff Forbes receives startling information.

Katherine chooses a new victim. Bonnie discovers new information about Mason and shares it with Stefan.

Stefan and Damon decide on a new plan to deal with Katherine at the masquerade ball.

As the full moon nears, Caroline helps Tyler prepare for his transformation. Meanwhile, Damon and Alaric are suspicious when a stranger shows up looking for Mason.

Johnathan Gilbert's return to Mystic Falls is an unhappy surprise to Elena, Jenna and Damon. Stefan does his best to reach out to a confused Tyler.

Stefan and Elena attempt a romantic weekend getaway, not realizing that they've been followed. Damon attends a tea at the Historical Society.

Isobel unexpectedly returns, leaving Jenna devastated. Bonnie attempts to harness her ancestors' power. Stefan and Damon realise that they have a new weapon.

Stefan and Damon are angry when they find out that Elena has taken matters into her own hands in the battle against Klaus. Tensions also rise between the brothers over the best way to protect her.

Damon reveals that he is willing to go to incredible lengths to protect Elena from falling victim to Klaus's plans. Stefan and Elena spend a romantic day together.

Lives hang in the balance as the consequences of the sacrifice ritual play out.

It's Elena's 18th birthday, and as she searches for Stefan, Damon tries to keep her from doing anything that might draw Klaus's attention.

Damon and Alaric reluctantly go along with Elena's new strategy to find Stefan, leading Damon into a dangerous fight with an unexpected enemy.

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. Stefan discovers that Klaus fears a vampire hunter, Mikael, and tries to get more information from Rebekah. She's suspicious of his attitude and tells this to Klaus, who decides to return to Mystic Falls.

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.

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.

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.

The present-day murders in Mystic Falls remind Damon of a similar crime spree a century earlier. Flashing back to 1912, Damon recalls a beautiful vampire.

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 they aren't careful enough, so Damon must intervene. Jeremy calls home from Denver, reporting that he only suffers from melancholy, but is doing well at school.

Klaus acts on his intentions to leave town with Elena, but finds resistance from a surprising new enemy. Damon and Stefan have a surprisingly candid conversation about the future.

Determined to protect his sister, Jeremy makes a decision that will change everything; Bonnie makes a secret deal that has heartbreaking consequences.

In the fourth season premiere, Elena awakens after the accident to find the thing she dreaded most has come true. Damon is furious with Stefan, and takes out his rage on Matt.

Stefan and Damon argue about what is best for Elena. Jeremy and Matt are surprised to see a girl they used to know, April (GRACE PHIPPS), enrolling at Mystic Falls High.

Elena learns confronting Rebekah (CLAIRE HOLT) can be dangerous. Tyler gets a surprise visit from Hayley (PHOEBE TONKIN - The Secret Circle), a werewolf who helped him with Klaus.

At the annual Miss Mystic Falls Pageant, Elena and Caroline give April (GRACE PHIPPS) advice, while Tyler and Hayley (PHOEBE TONKIN) work together on a secret project.

It's a winter wonderland in Mystic Falls. Plus, Professor Shane (DAVID ALPAY) reveals a piece of ancient history that leaves everyone speechless.

Rebekah (CLAIRE HOLT) is back with a vengeance. Bonnie is uncomfortable when her father, Rudy Hopkins (RICK WORTHY - Supernatural), accepts the role of Interim Mayor.