In early-to-mid 2012, Matt Donovan threw Tyler Lockwood a "Welcome Home" party after he returned from his revenge mission against Niklaus Mikaelson in New Orleans. The party took place at the Lockwood Mansion in the episode The Devil Inside.
At the party, Katherine Pierce—who was not only possessing Elena Gilbert's body with a Passenger spell following the death of her own body, but was also impersonating Elena in order to reap the benefits of living her doppelgänger's life—was desperate to learn where the Salvatore brothers had hidden her body so she could bring it back to Nadia Petrova and Mia and use it to cast a spell make her possession of Elena permanent. Stefan, believing that she was Elena, informed her that Damon wanted her back, but Katherine blew the question off in favor of asking him where Katherine's body under the guise of wanting to give her a funeral. Stefan replied that Damon hadn't told him where he buried her; he only said that he "put her where she was always meant to be." Upon hearing this response, Katherine realized that he put her body in the tomb under Fell's Church where Damon had believed she was trapped for almost 150 years.
Katherine tried to say goodbye to everyone before she left the party to head for the tomb, but Caroline Forbes, also believing her to be Elena, stopped her and insisted that she needed to talk about what had happened between her and Klaus the night Katherine "died." When Caroline confessed that she had slept with Klaus, Katherine was genuinely shocked for a moment, but when she saw Tyler coming down the nearby staircase, she loudly repeated that Klaus and Caroline had sex so that Tyler would hear them and get mad enough to allow Katherine to get away to do the spell.
Tyler became furious after this revelation and left the room while Caroline panicked about it in the dining room. She eventually found him in his bedroom and tried to apologize, but Tyler refused to let her explain and instead reminded her of all the terrible things that Klaus had done to all of them, including killing his own mother. Tyler then becomes so overwhelmed with fury that he yelled at her to leave, when when she didn't, Tyler let his hybrid face out. Just then, Stefan heard the commotion and came into investigate, and when he made a comment about Tyler's behavior, he told Stefan that Caroline had slept with Klaus. Stefan seemed shocked and betrayed at first, but he quickly got over it, and instead punched Tyler in the face before arguing that nothing Caroline did made her deserve the threat of being bitten by a hybrid.
Meanwhile, Elena was able to briefly regain control over her body while Mia was doing the spell to make Katherine's possession permanent, and she caught the two off-guard long enough for her to escape. As she ran toward the Lockwood Mansion, she was flooded by memories of Katherine's life once Mia recovered enough to continue the spell. Elena finally managed to find Damon and threw herself into his arms, but the second they reunited, the spell was completed, giving Katherine back full control of Elena's body.
Damon began to make a speech about how badly he had screwed up by breaking up with her and not giving her enough credit to believe that she could withstand his past. He then said that Elena was good, and that he needed good in his life because otherwise, it was full of darkness. However, after his plea to have "Elena" take him back, Katherine told him that not only did she not want to be the only thing that he lived for, but that she didn't want to have to worry about what he would do if they broke up. Unable to stop herself, she also told him that she couldn't get over how horribly he had treated Katherine while she was dying. Before she left the party, she told him that their break up was the right thing to do and insisted that their relationship was over, breaking his heart in the process. Once she left, Stefan, who had overheard their conversation, approached Damon to comfort him, but Damon rejected it and claimed that Stefan actually enjoyed witnessing that.
- Katherine, who had been possessing Elena's body as a Passenger since the death of her body in 500 Years of Solitude, attended the party impersonating Elena. Because everyone was under the impression that both Katherine's body and spirit were dead, they had no reason to doubt that Elena was really Elena.
- While impersonating Elena, Katherine "broke up" with Damon, which would eventually send him on a violent and self-destructive downward spiral.
- Katherine was ultimately successful in gaining permanent control of Elena's body.
- After briefly gaining control over her body for the last time this episode, Elena arrived to the party just in time to embrace Damon, who was unaware that Elena had a Passenger inside her, before Katherine regained control again.
- Katherine as Elena breaks up with Damon.
- Katherine, Stefan, Tyler and Matt all found out that Klaus and Caroline had sex in 500 Years of Solitude.
- Tyler didn't take it well and lashed out on Caroline.