Plot

Despite an unanticipated act of courage, events spin out of control in a frightening way.

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.—Claudio Carvalho, Rio de Janeiro, Brazil

With the arrival of the full moon, Elena tries to prepare for whatever Klaus has planned and Tyler faces his second transformation. The terrifying events quickly spin out of control, despite an unexpected act of courage. Finally, Damon admits the truth to Stefan about a terrible new development they must face.—CW Publicity

Picking up immediately where the previous episode left off, Caroline (Candice King) and Matt (Zach Roerig) try to fend off Tyler (Michael Trevino) the attacking werewolf, but the gate isn't holding. Matt shoots him with the rifle. Caroline super vampire speeds them away.

Meanwhile at Klaus' apartment, Damon (Ian Somerhalder) examines his werewolf bite. He accepts the situation calmly that he is dying. Katherine (Nina Dobrev) doesn't want him to leave angry. He thinks she made her choice when she lured Jenna (Sara Canning) out for Klaus (Joseph Morgan). Damon gave her vervane so she could resist. However, Katherine made the choice whicj saved her skin. Damon wants to offer himself as a replacement sacrificial vampire. Katherine thinks Klaus won't take him because his blood is impure.

In the woods, Jenna wakes up and doesn't remember what happened. She thinks Elena (Nina Dobrev) called her, but she now realizes it was Katherine. She remembers Klaus made her drink his blood. He brought them to the quarry. Elena reminds her how someone becomes a vampire. Jenna realizes Klaus killed her and that she is now a vamp. Before she can process the fact she's a vampire, Greta (Lisa Tucker) arrives. She traps Elena in a circle of fire. Greta opens a vein and offers her wrist to Jenna who only manages to resist for a minute and then drinks deeply. Greta traps them both. Elena tries to reassure Jenna it will be OK. As Jenna starts to turn, neither of them is aware that's true.

At the sanctuary, Bonnie (Kat Graham) and Jeremy (Steven R. McQueen) look through the grimoires for something to keep Elena from becoming a vampire. Elijah (Daniel Gillies) explains the curse is broken in three stages: first the werewolf is killed, then the vampire, then the doppelganger. When Elena dies, Klaus's hybrid werewolf side will be activated. Elijah tells Stefan (Paul Wesley) and Alaric (Matthew Davis) that he'll be vulnerable during the transformation. If Bonnie can deliver Klaus to the brink of death, Elijah will finish things himself. Just then, Damon calls Stefan. He tells him they have Jenna and turned her.

Jenna sits trapped in the circle of fire. She tells Elena she's terrified, but everything is heightened. Elena tells her she'll do whatever it takes to save her. Greta brings Jules (Michaela McManus) to the quarry and traps her in her own circle of fire. She's slowed down Jules' transformation, so she's in a lot of pain.

Caroline and Matt hide out at the Lockwood house. Matt reloads. He tells Caroline that he was on vervane and was spying to her mother. He says her mom hates vampires. She asks where it leaves them. "Stuck in this house, trying not to get mauled to death by our friend," he says.

At the Salvatore house, Damon starts to feel the effects of his bite, but answers the knock on his door. It's John Gilbert (David Anders). He's not happy to learn Damon fed Elena his blood.

Back in the quarry, Klaus hands the moonstone over to Greta. She drops it in the fire and begins chanting. Jules writhes in pain but manages to tell Elena she was just trying to help Tyler so he wasn't alone. Greta releases Jules from her circle of fire. She lunges at Klaus. He promptly rips her heart out in front of Elena and Jenna.

Jeremy finds a section in the book on Emily Bennett's resuscitative spell she hadn't quite finished. Rick drops by, with Elijah and Stefan upstairs. Ric tells Jeremy about Jenna. Bonnie wants to go take on Klaus herself. They remind her of the effects of using that much power. Stefan says they're going to offer another vampire, one that Klaus wants more: Stefan.

Back at the quarry, Klaus squeezes the blood from Jules' heart into the cauldron. Jenna remembers the day she agreed to be Elena and Jeremy's guardian. They argue over who failed who. Elena tells Jenna she should fight back and run when she gets the chance. Elena assures Jenna she'll be OK.

Meanwhile, Caroline and Matt wait for Tyler. Caroline worries that her own vampire hunting mother wants to kill her. They hear a noise at the door. Tyler is lying there naked and wounded.

Bonnie does a spell to find Klaus. Elijah reminds Stefan they have to keep Bonnie hidden until the last minute so Klaus doesn't know she's coming. Stefan worries whether Elijah can be trusted. Elijah tells him over the year Klaus has hunted down their entire family and killed them. He swears he won't fail. He wants revenge. John arrives where he brings the Gilbert journals to look for Emily's spell. Alaric tells Damon about Stefan's new plan. Damon's not a fan.

Back at the quarry, Klaus turns to Jenna. Elena begs with him to let Jenna go. Klaus turns to see Stefan standing behind him.

John says there's a spell to bind two souls. If they used it on Elena, she wouldn't be able to turn.

At the quarry, Stefan offers to take Jenna's place. Jenna hears and tells Elena.

At the Lockwood house, Caroline tells Matt that Tyler is OK and sleeping. Matt tells her things have been great with her lately. However, he's not sure he can get past "the whole vampire thing."

Bonnie casts a spell on John. When Jeremy insists on going with her, she kisses him and apparently knocks him out. She doesn't let Alaric leave either. Damon agrees.

Klaus brings Stefan down to the circles. He asks Elena to choose. Then he stakes Stefan to knock him out. He explains he has other plans for Stefan. Greta begins the next part of the spell. "It's Ok Elena, I know what I have to do," Jenna says. She races to Greta and bites her neck, but Klaus stakes her. Elena watches helplessly from inside the circle of fire and tells Jenna to turn off her emotions so she won't be scared. Elena screams as Klaus pins Jenna down and stakes her through the heart. RIP, Jenna. Stefan is alive, but immobilized by the stake through is back. He sees he's too late to save Jenna. Greta pours her blood on the fire. Stefan whispers to Elena he's sorry, but Elena only asks "Are they going to kill him?" Stefan says "yes". Klaus brings Elena over to the altar, next to Jenna's ashen body. Klaus bites down on Elena's neck. She calmly lets him. He drops her body to the ground. Elena lies there, not breathing. Stefan can only watch. The moon clouds over. Klaus says he can feel the change. He starts to creak and change into a werewolf but suddenly sparks erupt.

Bonnie walks out of the clearly chanting furiously. Damon runs forward and breaks Greta's neck with one swift movement and Bonnie immobilizes Klaus. "You were dead!" he shouts at Bonnie as he writhes. Damon removes the stake from Stefan, who tells him to get Elena out of there. Bonnie lays on the final bit of incantation. Elijah walks out and kneels over his brother, digging his hand into his chest. "I didn't bury them at sea, their bodies are safe. If you kill me, you'll never find them," Klaus tells him. Elijah pauses. Bonnie swears to kill them both if he hesitates. Elijah thinks about it for a minute, then apologizes and whisks Klaus away.

Stuck in the witch house, Jeremy asks John if he read the whole journal. He gives Jeremy a note to give to Elena along with his ring. He tells Jeremy that he and Elena should take care of each other. Damon brings the dead Elena into the house. Alaric asks about Jenna. Damon apologizes... to Jeremy. John walks out of the house into the rising sun. Inside, Elena takes a deep breath and begins to awake. She feels fine. Outside, John drops to the ground.

At the Lockwood house, Caroline plops down on the couch next to naked Tyler and his blanket. She tells him he got shot, but it's healing. Tyler thinks he shouldn't have come home, but she says he shouldn't have left. "You're kidding right, this is the second time I've tried to kill you," he says. Caroline tells Tyler that Matt broke up with her. He shares his blanket.

Stefan tells Damon that Elena is in shock from losing the only parents she ever had. Elena and Jeremy get ready for the funeral. He gives her the letter and ring from John. She tells him she's sorry he's lost so many people. "I still have you," he says. Elena reads John's letter. He says he failed her because of his prejudices. She has a chance to do better with her own child than he did with his. Elena lays roses on their graves. John's letter says whether she's reading the letter as a human or vampire, he loves her all the same. Alaric lays a rose on Jenna's grave.

Afterwards, Damon worries how they kill a half vamp-werewolf since Klaus is still out there. Stefan says he's not sure, but he doesn't want Elena to lose anyone else. Damon tells him not to make any promises. He tells him Tyler Lockwood bit him. Stefan says they can find a cure. Damon says all Stefan can do is keep it from Elena, who doesn't need to grieve anymore. Damon walks away, into an uncertain future.