|“||Ah, Caroline. Klaus had a thing for her. [...] And I'm pretty sure I snapped her neck once.||”|
Caroline and Hayley got off on the wrong foot from the first time they met, when Caroline assumed that Tyler was cheating on her with Hayley while he was living in the Appalachian Mountains. Despite the fact that the two allied together to help Tyler teach the rest of Klaus' hybrids to break their sire bonds, neither one of them really liked the other. The tension between the two women only increased when it became clear that Hayley was convinced by Atticus Shane to work with him in order to manipulate Klaus into killing his hybrids as part of his plan to create an Expression Triangle. From then on, the relationship between Hayley and Caroline could be considered that of enemies. However, with Hayley now living in New Orleans while raising her daughter for several years now and with Caroline running the Salvatore Boarding School while raising her twin daughters, they have had little to no opportunity to interact with each other since Hayley's betrayal.
Throughout The Vampire Diaries SeriesThe Rager, Hayley, a friend Tyler met while he had left Mystic Falls to break his sire bond to Klaus, came to visit Tyler at the Lockwood Mansion while he was on a "house arrest" imposed by Klaus following the hunter Connor Jordan's attempt to kill Tyler in front of the entire town. Later, Caroline stopped by the mansion to see Tyler, but he tried to prevent her from coming in, as he hadn't told Caroline about his friendship with Hayley yet. Caroline was hurt by Tyler's rejection and left. While the two were talking, Klaus came upon Hayley upstairs, who told her that Tyler had never mentioned her, and when Klaus overheard Tyler and Caroline's conversation downstairs, he assumed that the reason Tyler was lying to Caroline was because Tyler and Hayley had had an affair while Tyler was in the Appalachian Mountains. When Tyler returned to the lounge upstairs, he found Klaus waiting for him and Hayley gone. Klaus informed him that Hayley left, and then speculated aloud that Tyler was hiding Hayley from his girlfriend was because they had hooked up while Hayley helped Tyler break his sire bond, a remark that made Tyler extremely upset, though whether or not Tyler and Hayley truly had an affair has yet to be confirmed.
In The Killer, Caroline came to the Lockwood Mansion to inform Tyler that her mother had squad cars blocking the street across from the Mystic Grill, as Connor had taken Matt, Jeremy, and April hostage in order to use them as bait to kill the vampires and hybrids in the town. Once there, Caroline finally met Hayley, who casually explained that she was a friend of Tyler's, and that he had generously allowed her to stay with him a couple of days, a revelation that made Caroline furious because Tyler hadn't mentioned her. That night, Hayley and Tyler were drinking and mourning the death of their hybrid friend Dean, who was killed by Connor during the rescue mission, Caroline returned to the mansion to demand what was going on between Tyler and Hayley. It was then that Tyler finally confessed that Hayley really was just a friend, and that they were just allowing Klaus to believe that he and Hayley had a fling together so he wouldn't figure out the real reason they have been hanging out-- because Hayley planned to help him teach the other hybrids how to break their sire bonds, too.In We All Go a Little Mad Sometimes, Caroline brought Tyler's belongings over to the mansion, and when Tyler said that it wasn't a good time for them to do this, Caroline made a loud and dramatic scene in front of everyone at the house, including Klaus. Klaus, gleefully enjoying all of the tension between the three, said he would give them some privacy and took some of the hybrids with him to leave the house. Once he was gone, Caroline dropped the act and asked Tyler and Hayley whether they thought Klaus bought their fake fight. Tyler remarked that both Caroline and Hayley were good liars and kissed Caroline passionately, which made Hayley look away out of slight jealousy.
In O Come, All Ye Faithful, since Tyler and Hayley had successfully broken the sire bonds of Klaus's twelve remaining hybrids, Tyler's plans to bring down Klaus commenced as they had agreed. When Caroline discovered Tyler's plan entailed having a witch put Klaus in Tyler's body and encasing it in concrete to neutralize him for good without hurting any of the vampires or hybrids in his sire line, she suggested that they put Klaus' spirit in Rebekah's daggered body, thereby getting rid of two Original Vampires with one move. However, since Hayley was secretly working with Shane, and they had their own plans that involved informing Klaus that Tyler had helped the rest of the hybrids break their sire bonds, Hayley snapped Caroline's neck to keep her from further interfering with her plans, as Shane had promised to reunite her with her biological parents if she helped him with this task. When Caroline woke up after her broken neck was healed, she angrily muttered that Hayley had lost her mind and quickly informed the others about what had happened. After this, Hayley went on the run, and though she returned to Mystic Falls for a brief time, she and Caroline have not seen each other since.
Throughout The Originals Series
In A Streetcar Named Desire, although they do not interact whatsoever, Stefan Salvatore and Hayley are locked in the trunk of a car together to prepare to bring down Klaus' enemy. Stefan and her bond over their close relationships with the ones they love and Stefan mentions Caroline to her. Hayley humorously remarks that she "may have broken her neck once."
- Caroline: "Who are you?"
- Hayley: "Who the hell are you?"
- Caroline: "Caroline."
- Hayley: "Oh! You're Tyler's girl. Told me about you. I'm Hayley."
- Caroline: "Well, Hayley. That's pretty crazy, 'cause I haven't heard a thing about you."
- Hayley: "I've been staying here a few days."
- Caroline: "Excuse me?"
- Hayley: "I needed a place to crash. Ty's a buddy. It was kind enough to offer."
- Caroline: "I know all of Ty's buddies and I haven't heard about you. So, how about we cut the crap?"
- Hayley: "Yeah, I don't need teen drama. Take it up with Ty. Excuse me."
-- The Killer
- Caroline: "You think he bought it?"
- Hayley: "Hell, I bought it."
- Caroline: "Thanks for the heads up that he was here, Hayley."
- Caroline (after talking on the phone with Bonnie): "She said it would work."
- Hayley: "I gathered. Congratulations."
- Caroline: "Thank you."
- Hayley (suddenly snaps Caroline's neck): "My pleasure."
- Caroline (to Stefan on the phone after she woke up): "Stefan, it's me. That little werewolf slut has lost her mind. Go to the Lockwood cellar and make sure that Rebekah's body is still there. I'm gonna find Tyler. Hayley's trying to screw this up."
- Both women have slept with Klaus.
- Caroline does not know that Hayley was pregnant with Klaus's child.
- Caroline was jealous when Tyler and Hayley were hanging out.
- Both Hayley and Caroline have had feelings for Tyler.
- Both Hayley and Caroline were pregnant.
- Phoebe Tonkin and Candice Accola are real-life friends.