After a locator spell to find Elijah and a transportation spell to get there, they knock on the door just as Rebekah's car speeds to a stop in the driveway, where Kol sees Matt in the passenger seat.

"What's he doing here?" Kol asks bitterly towards Matt once they get out of the car.

"Relax Kol, he's here to help. Oh and Matt, if you don't mind I invited Caroline." Rebekah explains to Kol, then says as she turns to Matt and places her forehead on his cheek after kissing it, implying that they are in a relationship.

Elijah finally opens the door just as Freya, with her girlfriend Keelin, pull up and park by the curb since Rebekah's car apparently takes up the entire driveway.

"Who called her?" Davina says even more bitter towards Freya than Kol was with Matt.

"I did." Rebekah says and Davina growls at Freya.

"Can you guys come inside any day now?" Elijah asks impatiently and they all file in the house.

Once they all walk in, they see Katherine tending to a sick, 4-year-old Klaus.

"What the bloody hell is she doing here?" Rebekah asks being the bitter one this time.

"She's been helping me take care of him." Elijah explains as Matt just nods in Katherine's direction, unquestioning.

"She has?" Rebekah asks in a monotone and an even more bitter tone in her voice.

"Yes, she has." Katherine says in an equally bitter tone as she walks away from Klaus.

"So, how is he?" Davina asks breaking the bitter tension as she rushes to Klaus' aid.

"Besides the fact that he's sick and dying? I'm sure he's just dandy." Katherine asks and then states very sarcastically causing Davina to intently glare at her.

"That's a voice that definitely rings a few bells." Klaus says weakly causing Katherine to walk over to him.

"Zdravei, Katerina." Klaus says still weakly and manages to smirk at her before coughing up blood.

"Good to know he can speak Bulgarian, even when he's dying." Rebekah says clearly annoyed by what her brother can and can't do.

"I'm just glad his ego is still in check." Kol says slightly happy about the fact he just stated.

"Ok so the last time I cured this bite, I used Keelin's venom. I might be able to do it again with the right materials." Freya says trying to refocus everyone on the fact that Klaus is a dying 4 year old.

"She's right, we need to focus. Davina, do you think you can find a cure for this?" Klaus asks Davina, totally blowing off the fact that Freya offered her help.

"I might be able to. If I can reverse-engineer the aging spell, and add a few ingredients as well as remove some then yeah, I can probably find a possible cure." Davina says taking out and looking at the grimoires she brought.

"Possible? Darling, can't you be a bit more precise?" Kol asks clearly sounding worried about Klaus yet also distant from the situation.

"I'm sorry Kol, but possible is the best and only answer I can give you." Davina says not even glancing from the grimoire she's reading.

"Davina, you won't be able to find a cure before I die. You have to enact plan B." Klaus says weakly which causes Davina to look at him in shock.

"Klaus no, plan B is not an option we have right now." Davina says after she closes the grimoire and rushes to his aid.

"Sweetheart, plan B is the only option we have right now. You want to find a cure and I don't want to die, so just do it." Klaus manages to say before continuing to cough up more blood.

"What in the bloody hell is he talking about?" Rebekah asks confused as everyone else starts to shrug.

"Plan B is this. He helped me make it by letting me channel him." Davina explains as she holds up a gold dagger.

"You made a second one?" Kol asks confused on how she got the dagger.

"He let me use Elijah's since he wasn't going to be using it on him. So Elijah's dagger became his dagger. Klaus are you sure you want me to use this?" Davina explains then asks Klaus once she turns back around.

"Just do it, it's the only way unless you wanted to slow down the effects." Klaus says as he places the white oak ash in Davina's hand.

Davina dips the dagger in the ash, looks at him again to make sure and once he nods his head, she shoves it through his chest and watches his four year old self groan as he turns grey, implying he is in fact an Original again.

After a moment of silence, there's a knock on the door.

"I'll get it." Matt says as he walks over to the door and answers it.

"Oh hey Caroline." Matt says after he opens the door.

"Hey Matt. I hope you don't mind, I brought some company with me." Caroline says as she walks in the house with Finn and Sage following behind her.

"Finn?! Sage?!" Kol asks very surprised and happy to see them as runs towards them.

"Your welcome." Caroline says even though no one thanked her or even know what she did.

"How is this even possible?" Kol asks still very excited, much like a child.

"I'll explain it later. So Rebekah calls me and I come, even though I have no idea what's going on." Caroline says scanning around and then looks at Rebekah for answers.

Before Rebekah can say anything, Caroline realizes that Katherine is there and her eyes follow where Katherine's facing to see a grey four year old.

"Did you turn and kill a four old? Who's kid is that?" Caroline asks concerned sounding as glum as everyone looks as Davina is looking through grimoire after grimoire.

"No, no one turned and killed a four year old. That is Klaus." Katherine says which makes Finn and Sage's jaws drop, in disbelief and Caroline to just look shocked yet also slightly upset.

"How it happened is a long story for another time." Davina says quickly before anyone could even ask.

"Ok so this spell teaches me how to make food that will always taste good. Not what I'm looking for but definitely keeping." Davina murmurs then flips the page.

Hours pass and Davina finally gets to a third grimoire but she starts turning the pages so quickly, no one's sure if she actually reads that fast or is just fanning herself with the book.

"My god, I think I found it!" Davina exclaims excitedly causing everyone to look up at her.

"What, the cure?" Rebekah asks a little too hopeful.

"What no, I found a spell that can make tacos appear right in front of you and I thought we could use a food break." Davina says and everyone looks at her like they're judging her.

"I thought you were looking for a cure to this." Freya groans impatiently.

"Well maybe I'll prolong my search and eat my tacos incredibly slow too all because you gave me attitude just now." Davina says bitterly as she really emphasized and to prove she's even more so towards Freya.

"Davina darling, focus." Kol says in a wary tone.

"What, I think I deserve to be bitter towards her! You should be lucky I'm not angry at you or Elijah!" Davina shouts as she unintentionally gives Freya an intense migraine and lights the candles which causes the flames to get higher.

"Davina, I'm not saying that you don't deserve to be, I'm just saying you should save Klaus before you burn this place to the ground." Kol says causing Davina to calm down after she realizes that she lit all the candles.

"I'm sorry, I thought I was in control. Being dead just made me lose control of my magic, I blame Freya." Davina says as Kol comforts her.

"She almost killed me with her unstable magic!" Freya yells obviously believing she deserves attention.

"Oh shut up, nobody cares about your opinion. From what I'm hearing, you definitely deserved it and I don't even know what you did." Caroline says impatiently and also annoyed by Freya as well as defending Davina, even though she doesn't know either of them, impressing a few of the people in the room.

"Davina, right? If I put that bitch on a leash, can you please keep trying to find a cure?" Caroline says calmly handing Davina a different grimoire with a small, reassuring smile.

Davina takes the grimoire from Caroline, returning a similar smile as well as a small nod.

Davina sits on the coffee table that's next to Klaus and starts reading spells that could possibly work as though as he'll respond to her.

Behind Davina, on a different table, is a lot of witch ingredients along with her bag and other grimoires, which Caroline glances at and then walks over to the table to browse all the ingredients.

After watching several test subjects melt or implode, Davina is sitting on the chair next to the table of ingredients still reading the grimoire as Caroline impatiently paces, reminding a few people, mainly his siblings, Sage, and Katherine, of Klaus.

"Ok yeah yeah blah blah, we got it." Caroline says impatiently as she closes and takes the grimoire from Davina, annoying her.

"I was reading that." Davina says showing her annoyance.

"Yeah and I was getting a headache. Move over." Caroline says showing the fact that she's impatient and annoyed.

"What, Why?" Davina asks confused yet still annoyed.

"This isn't my first rodeo, I think I might know what the cure is. Move, please." Caroline says and Davina moves aside so Caroline can sit down.

Caroline starts looking at three different grimoires at once, murmuring under her breath while putting random measurements in different bowls.

"Alright, do you have any extracted venom?" Caroline asks turning to face Davina.

"Yeah, there's two left. Here." Davina says as she hands them to her.

"Fantastic, thank you Davina." Caroline says as she takes them from Davina and turns back around to continue intently focusing on the cure.

Caroline injects the two syringes into the bowl and it changes to a maroon-ish color.

"That's a good sign. I just need the blood of any or all siblings, and the blood of the witch who casted the previous spell on him." Caroline explains, clearly hoping this will work, as all of Klaus' siblings drop their blood in the bowl making it turn more of a dark purple-ish color.

After Davina finally admits to being the witch, Caroline bites her wrist, places it over the bowl, and presses on the wound so more blood comes out.

Once the cure turns into a reddish purple color, Caroline rips part of her own shirt off, wraps it around Davina's wrist, and pats it then mouths 'thank you' to her.

"Alright a drop of blood of the ones he loves most." Caroline murmurs as Hope pricks her finger with the bobby pin in her hair and drops some of her blood in the bowl causing it to turn slightly darker.

Once Katherine realized what Caroline murmured meant, she pricked Elijah's finger and put more of his blood in the bowl making it even darker.

"Now that that's over with, the blood of his soulmate?" Caroline asks herself and has confusion in her murmured tone.

"Does he even have one of those?" Caroline asks still murmuring to herself with confusion and disbelief in her tone.

"Well, better take safety precautions." Caroline says continuing to murmur under her breath as she pricks her own finger with one of her fangs and presses on the wound so she bleeds in the bowl making it turn the color it's supposed to.

"Is it done?" Davina asks curiously.

"I think it is." Caroline says sounding slightly unsure about the cure she just made.

"Great, a finished cure and no test subjects. That- that is just bloody fantastic." Rebekah says bitterly which causes Caroline to just smirk with an idea.

"I wouldn't say we don't have any test subjects." Caroline says emphasizing any which catches everyone's attention.

"Uh, Rebekah's right. I'm not seeing any dying test subjects in need of a cure." Davina says sarcastically looking around.

Right when Davina finishes that statement, Caroline vamp speeds over to Klaus, bites down on his visible arm, which has the wound on it, and lifts her head up trying to ingest it instead of puke it up.

"Now you do." Caroline says with blood on her face and breathing heavily after the venom goes down, leaving everyone in shock of what she just did.

"You know one of us could've done that, right?" Rebekah asks breaking the shocked silence.

"Yeah, but rather me than you." Caroline says still out of breath as she walks over to the table and picks a vile of the cure she made.

"Let's pray this works." Caroline murmurs after she opens it and then drinks it like she's taking a shot of alcohol.

Once the cure has proven to work on her, she walks over with a different vile and pours it down his throat after she has Davina remove the dagger.

After two hours have passed, the four year old turns into Klaus' adult form which leaves everyone impressed and shocked.

"It won't be long before he wakes up now." Caroline says proud of herself and is about to leave yet stops in front of Davina.

"You can tell him you found and made the cure, it was your promise after all." Caroline says confidently yet slightly upset, causing Davina to look down sadly and with that being said, Caroline walks out of the house.

After Caroline walks to her car, she drops her keys.

"Just great." Caroline murmurs as she bends down to pick up her keys until she hears the sound of vamp speed near her.

"Hello?" Caroline asks as she stands up to look around, with her keys still on the ground.

"Oh my god." Caroline whispers after she turns around to see Klaus now in front of her.

"Hello Caroline. Did you honestly believe I wouldn't have figured out that you saved me?" Klaus asks with his usual Klaus smirk.

"Actually, I thought I'd be half way out of town before you woke up." Caroline states and Klaus looks at her with an understanding nod.

"Well, you don't need to worry about leaving sweetheart because I'm the one who's leaving." Klaus says and Caroline looks at him confused.

Klaus realizes she is confused so he holds up his arm after he lifts up his sleeve to show her the bite wound.

"That shouldn't be there I healed you." Caroline says starting to worry.

"You cured the deaging spell, not the bite." Klaus explains which makes Caroline upset.

"I personally tested it on myself and it worked. What did I do wrong?" Caroline asks holding his arm and looking intently at the bite wound.

"You did nothing wrong, Caroline. The witches who sped up the spell ensured that the bite would only temporarily disappear once a cure was found but then return after the deaging spell was fixed." Klaus explains and Caroline just looks upset.

"Well, I should probably go, so you can spend your last moments with your family." Caroline says walking past him to her car, as his back was facing the car, but he grabs her arm, causing her to face him at an angle, and pulled her closer.

"I've already said the goodbyes I needed to towards my family." Klaus says and Caroline partially opens her mouth, about to say something, but Klaus cuts her off by placing a singular last kiss on her mouth.

"Klaus…." Caroline starts after the kiss but Klaus starts choking up blood again as well as slowly falling yet before Caroline could do anything, Katherine runs to his aid with Elijah by her side.

"Niklaus." Elijah says very worried.

After everyone that was in the house is outside surrounding him, Klaus just looks around at everyone than looks Elijah in the eye and just smirks at him.

"I love you, Elijah." Klaus says weakly and then smiles, so you can see his teeth which are covered in blood, then stops smiling as he turns gray with his eyes open.

Katherine and Elijah back up as his body burst into flames and Katherine hugs Elijah from the side just as upset as Elijah is, with his last words ever being said.