A NIGHT OF CONFESSIONS - Katherine's mind games are getting on everyone's nerves, but Damon, Stefan and Elena realize that her knowledge of Mystic Falls history will help them stay alive. Frustrated with her relationship with Matt, Caroline finds a new way to get his attention. Alaric makes a surprising confession to Jenna, and Katherine makes a different kind of confession to Damon. Stefan and Bonnie try to convince Jonas and Luka that they should all be working together, but Jonas' lack of trust leads to violent and fiery confrontation.
The episode opens with Katherine playing with Stefan and Damon's minds by impersonating Elena. When Elena discovers that Katherine is out of the tomb, she is furious and tells Katherine to leave. Katherine insists that they all need her to help them kill Klaus and when Damon tells her to give them the information or leave, but she just threatens them.
Meanwhile, Caroline spots Matt putting up a poster for a band at the Mystic Grill. They both admit that they haven't heard from Tyler and Matt explains that he thinks Tyler said goodbye to him without him realizing. Caroline tries to talk to Matt, but finds it difficult and eventually, he gets frustrated, telling her that she knows how he feels and to make a decision. Meanwhile, Elena and Stefan arrive at school. Stefan points out that Katherine probably does know more than they do about Klaus. However, he suggests that he should stay at Elena's that night. Elena admits that he can't as she is having a girly night with Bonnie and Caroline, sarcastically adding that Katherine might join them.
Back at the Salvatore house, Damon tries to destroy Elijah's body with a flame-thrower, unsuccessfully. Katherine appears to reveal that she wanted to get out of the tomb no matter what and explains that she knew Damon would die. Stefan informs Bonnie and Jeremy that Katherine is back. He asks them to speak to Luka and Jonas to see if they can work together. Later, Stefan and Bonnie meet Luka and Jonas at the Grill to tell them that Elijah is dead. They suggest that they can work together to kill Klaus. Luka and Jonas return home and Luka seems receptive to the idea, but Jonas tells him that Stefan and Damon are their enemies and need to be dealt with. Luka asks if he is going to kill them, and Jonas says that he will let Elijah do it. Meanwhile, Alaric tells Elena that Jenna has started asking questions about Isobel.
He reveals that he can't lie to her while he is with her. Elena admits that it is getting more dangerous for Jenna not to know what's going on, but explains that she wanted to leave it until Klaus had been dealt with. Alaric promises to respect Elena's decision about whether or not to tell Jenna. Later, Elena, Caroline and Bonnie begin their girls' night when Jenna appears. She agrees to hang out with them as she is still upset about Alaric hiding something from her. Caroline suggests that Alaric might have a good reason for keeping something from her.
She reveals that there is a live band at the Mystic Grill and they decide to go. Back at the Salvatore house, Damon reads Jonathan Gilbert's journals in an attempt to find out the site of the witches' massacre. Katherine reveals that Emily Bennett told her about that and explains that when a witch dies, a mystical energy marks the place of death. Stefan arrives after his meeting with Luka and Jonas and explains that Elijah had no weapon to kill Klaus. He reveals that Elijah thought if a witch could channel enough power, he wouldn't need one and Damon realizes that's why Elijah wanted to find the site of the witches' massacre.
Meanwhile, Jonas takes Luka's hand and casts a spell to send Luka's spirit to find Elijah's body. Luka's spirit arrives at the Salvatore house and sees Katherine - although he thinks it is Elena - reading with Damon. He heads downstairs as Katherine moans that she is bored. She asks Damon if he has discovered the site of the massacre and he says he hasn't. She announces that she is hungry and goes downstairs to get some blood. Luka sees her in the cellar and Katherine feels his presence, but can't see him. Stefan arrives home and Damon claims that he can't find any mention of the massacre site, but silently shows Stefan a page.
Meanwhile, Luka crouches by Elijah and Katherine appears at the cellar door. As Luka pulls out the dagger, Katherine sees it and rushes to push it back in. Luka tells his father that 'Elena' is stronger than him, but Jonas reveals that it is actually Katherine and tells Luka to stake her. Luka goes to find a stake and knocks something over, causing Katherine to shout for Damon. Luka stakes her as Damon arrives, and rushes over to her. Katherine points out that the dagger is coming out again as Stefan arrives.
Damon grabs the flame - thrower and, back at his house, Luka is consumed in flames. Damon yells at Stefan to go over to Luka and Jonas' house. Meanwhile, Luka is severely burnt and Jonas bends over him. He grabs his Grimoire and casts a spell, but Luka remains lifeless and Jonas cries as he looks at him. He becomes angry and starts getting Elena's belongings that he took from her house. Stefan arrives and Jonas casts a spell to cause him to scream in pain. Jonas yells that he has no-one left and Stefan is about to find out what that feels like. As he leaves, Stefan sees a photo of Elena on the floor.
Jenna, Elena, Bonnie and Caroline arrive at the Mystic Grill. Jenna goes to get a drink and Alaric joins her, admitting that he hates that she is upset. Jenna insists that she can handle whatever he is keeping from her, as last year she was a grad student and now she is a parent. She walks off. Meanwhile, Bonnie and Elena urge Caroline to do something about Matt as Elena points out that although she is trying to protect him, he is still getting hurt. Caroline decides to get up on stage and announces that a guy asked her to tell him how she feels. She admits that it is not easy, but decides to sing.
She compels the band to let her perform with them and sings 'Eternal Flame'. Matt is impressed and gets up on stage to kiss her. Later, the duo are kissing in the bathroom and Elena accidentally walks in on them. She leaves and bumps into Bonnie, who asks if Elena would be alright with her dating Jeremy. Elena is shocked, but gives her permission and they hug. Stefan rings Elena, but she can't hear him, so goes outside. Meanwhile, Jonas arrives and Bonnie spots him.
Back at the Salvatore house, Katherine is recovering after being staked. Damon hands her some blood, but then stakes her in the side as revenge for not telling him the dagger would kill him. He tells her to start talking and Katherine admits that John and Isobel want Stefan and Damon out of Elena's life. She reveals that John offered her a deal - he knew killing Elijah would get her out of the tomb so he gave her a choice, to stay and help with Klaus or he would kill Stefan. Damon points out that John tried to have him killed and Katherine reveals that part of the deal was that she could only save one Salvatore brother. Damon is upset that she chose to save Stefan and walks off. Later, he leaves after hearing that Jonas is going after Elena. Katherine says that she has a plan and asks to go with him.
At the Grill, Bonnie approaches Jonas, but he asks her where Elena is, adding that Luka is dead. He says that the only way he has a shot at getting his daughter back is if he has Elena. Bonnie refuses to say where Elena is, so Jonas uses his magic to smash lights in the Grill and cause panic. Katherine and Stefan find Caroline and update her on the situation, adding that they need her to help with the plan. Back in the main room, Bonnie begs Jonas not to do anything, but he smashes glasses and sets the bar on fire, before using his magic to knock Bonnie to the ground.
Matt tries to put out the flames, but spots Bonnie on the ground and rushes to her.
Meanwhile, Katherine - pretending to be Elena - shouts to Jonas and asks him to let them help get his daughter back. As she distracts him, Caroline rushes in and bites him. However, Jonas resists and fights back. Matt arrives, telling Jonas to get away from her. Jonas smashes a bottle and stabs Matt in the neck. As he lies on the floor bleeding, Caroline is forced to feed him her blood to heal him.
Back at home, Bonnie admits that she feels bad that Luka died, but Jeremy says that he doesn't. Bonnie adds that she hated not being able to help. Katherine - still pretending to be Elena - returns with Stefan and Stefan asks if Bonnie and Jeremy checked the house. Katherine goes upstairs to the bathroom and Jonas appears behind her.
She turns round and bites him, killing him. Bonnie appears and says they didn't have to kill him, but Katherine insists they did. Bonnie touches Jonas, but he wakes up and grabs her. Stefan quickly breaks his neck to kill him properly. Meanwhile, Elena and Damon arrive home. Elena asks how they convinced Katherine to help and is worried when Damon reveals that it was Katherine's idea. Katherine returns and hands over Elena's necklace. Elena says that she will have to be gone before Jenna returns, adding that Katherine's help hasn't changed how she feels about her.
Katherine replies that she doesn't like Elena either and would be happy to see her dead, but needs her to take on Klaus. She insists that she isn't a threat to Elena. Outside, Alaric walks Jenna home and tells her that Isobel is dead, although there are some things about her death that he can't reveal. He adds that he loves Jenna, but she just goes inside. Upstairs, Jeremy admits that he is worried about Bonnie because the only witch who could have given her back her powers is dead. However, Bonnie reveals that when Jonas grabbed her, he returned her powers. She adds that Jonas wants her to kill Klaus and Jeremy replies: "Did he include a how?" Bonnie reveals that he did and kisses Jeremy.
At the Salvatore house, Damon works out that Katherine was the one who turned Emily Bennett in, causing her to be killed. Meanwhile, Katherine says that she can't figure out why Damon won't tell her the site of the witch massacre. She suggests that he must know it because he knew that Emily was the key to getting Katherine out of the tomb and would have wanted to make sure she was safe. Katherine suddenly starts flirting with Damon and climbs over him to kiss him, but Damon simply pushes her off and she walks away, annoyed.
Meanwhile, Matt wakes up and Caroline is forced to admit that she is a vampire and saved him with her blood. She insists that everything is going to be fine because they love each other, but Matt is shocked. He realizes that Vicki mentioned vampires before and asks what Caroline did. She insists that she hasn't done anything, but Matt tries to leave. Caroline refuses to let him go, but Matt is upset and angry and yells at Caroline: "What did you do to my sister?" Caroline begs him to calm down.
The episode ends with Jenna and Elena eating ice cream in the kitchen. Someone rings the doorbell and Jenna goes to answer it. Elena is curious, so she follows. When she gets there, she hears someone saying: "Hi, you must be Jenna. I'm Elena's mother." Elena sees the person at the door and realizes that Isobel has returned.