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.
Stefan meets with Dr. Jonas Martin and proposes to team-up with him to vanquish Klaus. The warlock refuses and uses astral projection to send Luka to the Salvatore house to save Elijah. However, Damon stops the removal of the dagger and uses a flamethrower to burn the invisible Luka to death. Dr. Jonas goes to the Mystic Grill to revenge the death of Luca by attacking Elena, but Bonnie lures him, and together with Damon and Stefan, they kill him. Caroline uses her blood to save Matt after Dr. Jonas' attack, and he is confused with that revelation. Alaric does not tell the truth about Isobel to Jenna, and she has a surprising visitor at the Gilbert house.
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 a violent and fiery confrontation.
- Elena helps make Stefan late for school by getting him back into bed.
Downstairs, Elena says good morning to Damon. Damon thinks she's Katherine and grabs her. She doesn't understand why he'd be confused -- she still thinks Katherine's in the tomb. And then Stefan joins the scene and wonders who he just rolled around in bed with. He races upstairs and grabs the Elena he was with. She thinks Katherine is in the tomb, too. Then the Elena from downstairs appears in the doorway. It's Katherine, apparently it's getting easier and easier for her to pass for Elena.
Later, Damon explains how Elijah's compulsion was broken when he was killed. Katherine says they'll want Klaus dead and need her. They want her to leave, but she threatens to hit the Grill and pass for Elena.
At school, Caroline sees Matt in the hall. He mentions that Tyler came by and saw him before he left town. He asks her what's going on and tells her to make up her mind or leave him alone.
Elena and Stefan arrive at school. She's not excited about Katherine staying with them.
Damon uses a blow torch to toast Elijah to get the dagger back, but his dead corpse won't burn. Damon asks Katherine why she didn't warn him that the dagger could kill him. She assures him she just wants to stay to kill Klaus. Katherine says she knew he'd die, she just wanted out of the tomb.
Stefan asks Bonnie to talk to Luka about helping with Klaus.
When they're alone in the hall, Jeremy tries to kiss Bonnie. She agrees they'll tell Elena soon.
Meanwhile, Ric tells Elena about John stirring up Jenna's suspicions about Isobel and of the existence of the vampires and werewolves. He wonders how much longer they can keep her in the dark. Elena isn't against telling her aunt the truth about what is going on, but wonders if they should wait until after they deal with Klaus. Ric leaves the decision about whether to tell Jenna the truth to Elena, but says he and Jenna are over until he can be honest with her.
Luka and Jonas join Stefan at the Grill. He tells them Elijah is dead. They offer to work with them to get Jonas' daughter back and kill Klaus.
At the Salvatore house, Damon reads the diaries, trying to figure out where a bunch of witches were massacred in town centuries ago. Katherine says when a witch dies violently, they release an energy marking the site of their death with power. Just then Stefan returns saying that Elijah didn't have a weapon to kill Klaus, but he thought if you could harness enough power, a weapon wouldn't be necessary. Like power from a spot marked with 100 dead witches.
Luka goes home and tries to convince his father to work with the Salvatores in order to rescue his sister. Jonas thinks Elijah is their best bet to get his daughter Greta back. He's going to let Elijah kill them.
'Girls' night at Elena's with Bonnie and Caroline.'
Jenna wanders through and joins in. She mentions Ric is hiding something about Isobel. Caroline argues that he might be trying to protect her. Caroline suggests they go see the band at the Grill.
Luka and his father prepare for a ceremony. Luka focuses on Elijah and suddenly he's in the Salvatore house, where Damon and Katherine (he thinks it's Elena) are reading. Damon reads in the John Gilbert journals that Emily Bennett was killed on the same site as the massacre. Katherine announces she's hungry and goes for blood in the basement. The projection of Luka follows her down.
Damon shows Stefan something in one of the books, while saying aloud that he hasn't found anything.
In the basement, astral Luka starts to remove the dagger from Elijah but Katherine sees him and pounces on it. Jonas realizes it's Katherine and tells his son to stake her. A chair breaks. Katherine yells for Damon. He comes downstairs in time to see Katherine holding onto a stake in her gut. Damon pulls the stake out then sees the knife in Elijah's chest moving again. He picks up his flame thrower and torches Elijah, and Luka, although he can't see him. Stefan runs downstairs. "It's some kind of crazy a--psychic witch attack!" Damon says, telling him to do something about it.
Back with Jonas, Luka bursts into flames. His dad manages to put him out, but he's dead. A spell doesn't help.
Meanwhile, the girls, Elena, Caroline, and Bonnie, arrive at the Grill. Ric and Matt are both there. Jenna tells Ric that whatever secret he's keeping from her, she can handle it. Caroline tries to figure out what to do about Matt. Elena says Ric's in the same boat with Jenna, trying to protect her, but hurting her. When the song ends, Caroline runs up on stage and takes the microphone. She realizes she has no idea what to say. She announces she's going to sing, then compels the band to back her. She sings the Bangles "Eternal Flame" -- very well.
Jenna moons over Ric. Caroline gets halfway through the song when Matt joins her on stage and kisses her deeply.
Stefan busts into Jonas' house and Jonas puts the witch mind clamp on him. Jonas tells Stefan that Luka is dead and now he's alone, and Stefan is about to learn what that feels like. Jonas leaves. Lying helpless on the floor, Stefan sees that Jonas had a picture of Elena.
Damon brings Katherine a restorative bag of blood for her staking. But first he stakes her again in the stomach -- payback for not telling him the dagger would kill him. He tells her to 'fess up. Katherine says John Gilbert and Isobel want Damon and Stefan out of Elena's life and offered her a deal. Either Katherine stays and helps with Klaus or he'd kill Stefan. Part of the deal, she could only save one of them. Damon realizes she chose Stefan.
At the Mystic Grill, Matt and Caroline make out in the bathroom. Bonnie finds Elena and asks if it would freak her out if she started dating Jeremy. Elena says he deserves to be with someone as amazing as Bonnie. Stefan calls.Elena goes somewhere to try to hear him on the phone. Bonnie sees Jonas walk in.
Damon wants to leave to go after Jonas. Katherine says she knows what to do.
Jonas tells Bonnie that Luka is dead. He asks where Elena is. When she doesn't tell him he blows out the electricity in the club. Matt and Caroline briefly pause making out and Matt goes to inspect the power outage. Stefan and Katherine find Caroline and catch her up to speed. They have a plan.
Back in the Grill, Jonas is mind-throwing glasses and starts a fire. People run screaming. He knocks Bonnie out. Ric gets Jenna out the building. Matt picks Bonnie up off the floor.
Katherine (as Elena) tells Jonas to let them help him. He starts some more fires. Caroline pounces on Jonas, fangs bared, but he mind-tosses her off. Matt sees Caroline scream and runs at Jonas. Jonas breaks a bottle and drives it into Matt's neck. Jonas leaves. Caroline runs to Matt. She chomps on her wrist and feeds her blood to Matt as he looks at her, horrified that she is a vampire.
Later, Bonnie tells Jeremy she felt useless at the Grill against the powers of Jonas. Stefan and Katherine/Elena come home. They ask if Bonnie and Jeremy checked the house. Katherine goes upstairs and finds Luka waiting in the bathroom. She chomps on his neck. Bonnie and Stefan come upstairs. Bonnie says they didn't have to kill him. Katherine argues they did. Suddenly, Jonas sits up and puts his hands on Bonnie's head. She screams and Damon snaps Jonas's neck.
Later, Damon tells Elena the plan was Katherine's idea. Elena isn't inclined to show Katherine any thanks. Katherine says she's not a fan of hers either, but she needs Elena alive to take on Klaus.
Outside, Ric tells Jenna that he understands if she's mad. He says Isobel is dead but there are things about her death that he can't tell her, that aren't for him to tell. He tells her he loves her. Jenna says good night.
Upstairs, Jeremy tells Bonnie he's worried about her, now that the only witch that could have given her her powers back is dead. He says he's there for her. She kisses him, then dims the lights -- with her powers. She says Jonas gave her her powers back when he grabbed her. He wants her to kill Klaus. And he told her how.
At Damon's house, he asks Katherine how the town knew Emily Bennett was a witch. She calls Emily a loose end. She knows Damon knows where the witch massacre site is. She tries to cozy up to him, but he shoves her off.
Matt wakes up in bed. He remembers drinking Caroline's blood. She tells him vampire blood heals humans. She says she's going to explain everything to him and it will be fine because they love each other. He freaks out. He remembers his sister Vicki saying something about vampires when she was in the hospital. He panics, but Caroline won't let him leave.
At the Gilbert house, Jenna eats ice cream. Elena joins her in the kitchen. The doorbell rings. Jenna answers. A woman stands there. She says she's Elena's mother. Elena sees her. It's Isobel.....