Shaking his head to clear the sex-crazed haze, Damon stared at the scene before him. Stefan had Marissa pinned against the wall by her throat. One minute Damon and Marissa had been ripping each other's clothes off and the next minute Damon had found himself yanked away from her.

"I refuse to let you get to him again," Stefan snarled.

"Mmm, you want to take his place, little brother?" Marissa suggestively ran her tongue over her teeth.

"Stefan, what are you doing? I thought I told you to go," Damon hissed. "Let her go. Rissa is my problem, not yours."

"Get back to Elena."

Chuckling, Marissa reached out and stroked her hand up and down Stefan's arm. "Yes, baby. Run back to your little human while little brother and I get reacquainted."

"Cut it out, Rissa." Damon glared at her. "Katherine will rip you to shreds. She's a lot older than you, remember? You wouldn't stand a chance against her."

Winking, she said, "True. But you wouldn't let her hurt me. You and I both know that you won't let anyone hurt me."

Stefan pressed his arm against her throat even harder. "Why should my brother do anything to protect you? What is it that you have over him?"

Although Damon hated to admit it Marissa was right. He couldn't let anyone else hurt her. Remembering that promise transported Damon back to that fateful night.

Damon stared down at the lifeless body of Marissa's brother Jack. He had snapped the worthless man's neck after seeing Marissa's bruised and bleeding face again. He'd warned Jack repeatedly about laying his hands on Marissa.

"Damon, what have you done?" Marissa had cried as she ran into the room. "Jack was all I had left! Now I have no one to take care of me!" And Marissa had flown against Damon, her hands pounding against his chest. "Now I have nothing!"

"Stop." Damon had grabbed her by the wrists. The realization that he'd just made the girl's life worse instead of better hit him like punch in the gut. She was right. It was a man's world. "You have me. I'll take care of you, Rissa. I'll protect you forever."

Her teary green eyes looked at him. "You promise?"

"I promise." He had hugged her to his chest. "As long as I'm around I will never let anyone hurt you again. Ever."

"Stefan, let her go." Damon reached out to grab Stefan by the shoulder. "I can handle her."

"Told you." Marissa smirked. "He might not want to, but your dear brother loves me."

Releasing Marissa, Stefan whirled around to face Damon. "You don't owe her anything anymore Damon! It's time to let her go. She gets into your head and fucks with your mind, Damon. And then you get all psycho crazy. That can't happen right now!"

"You are so fucking hot when you're on human blood." Marissa rubbed up against Stefan.

"Can it, Rissa." Damon stepped between them. "Let me make one thing clear. You. Are. Not. Fucking. My. Brother. If you do then we are finished. Once and for all."

Pouting, Marissa batted her eyelashes at him. "You don't mean that, baby. You could never deny yourself of me. Look at what almost happened before little brother showed up."

Narrowing his eyes, Damon said, "I mean it. You leave Stefan alone or I'll never fuck you again."

Throwing her head back in a hearty laugh, Marissa's eyes glittered in amusement. "You and I both know that I'm the one who does the fucking. Now, either I fuck you or I fuck little brother. Which one is it going to be?"

Staring at Marissa, Damon considered his options. He could just walk away and leave Marissa with Stefan, wash his hands of her once and for all. On human blood Stefan was stronger. Stefan would be able to handle whatever Marissa could dish out. Shit. Damon knew that was a lie. He knew firsthand what Marissa was capable of. And he knew that there was no way in hell his brother could handle it, human blood or not. Stefan wasn't damaged enough.

Besides, Klaus had made it pretty clear that Damon's first mission was to have sex with Marissa. Even if he lost Elena because of it, she would remain safe from Klaus. For the time being, anyway. And that was all that mattered to Damon at this point anyway.

"Let's go." Damon took Marissa by the elbow. "Where are you staying?"

"Damn it!" Stefan grabbed Damon by the front of his shirt. "Think about Elena, Damon. If you get involved with Marissa again then you'll lose her. Trust me."

The blazing pain in Stefan's eyes told Damon that he was right. Even on human blood, deep down Stefan was still Stefan. Part of Damon was glad that his brother was still holding on to his humanity. The other part of him hated him for it. It wasn't fair that Stefan was so much stronger than Damon, so much better than him.

Cringing, Damon said, "You still love her."

Stefan released Damon and turned away from him. "Of course I do. You should know how hard it is not to love her."

"She knows that you know."

Shaking his head, Stefan looked at him. "I told her earlier that the only reason I was ever with her was because she reminded me of Katherine."

Inhaling sharply, Damon's eyes widened. Stefan was right. By throwing Katherine in Elena's face like that Stefan had signed the death certificate on their relationship.

"Shit." Stefan looked behind him. "Where the hell did she go? It's not like Marissa to duck out on an opportunity to pit us against one another."

"Fuck." Damon knew exactly where Marissa was going. "Elena."

Feeling the air shift around her, Elena opened her eyes to see Katherine standing at the foot of Damon's bed. And for a split second, Elena thought she might have seen a whisper of concern in Katherine's eyes.

"You came." Elena pushed up into a sitting position. "Thank you."

Katherine crossed her arms over her chest. "You should be thanking me. It wasn't easy sneaking away from Klaus.

"You said you needed my help with something. This is becoming a habit."

"I want to get rid of Marissa."

Arching a brow, Katherine unfolded her arms and put her hands on her hips. "And by 'get rid of' I assume you mean kill her?" When Elena nodded, Katherine shook her head. "I can't kill her."

"I figured as much since Klaus is using her to try to break me and Damon up."

Admiration glittered in Katherine's brown eyes. Her dark red lips curved into a devilish smile. "I have to admit that I'm impressed. Instead of crying over Damon and Marissa, here you are plotting to kill her."

"Katherine, it's Damon. I'm not just going to wrap him up in a bow and hand him to her."

Laughing, Katherine said, "Klaus is right. You do the Petrova bloodline proud. So now that you know that I can't kill that bitch, tell me what exactly is it that you need me to do."

"You'll help me?"

"Elena, it's Damon." Katherine smirked as she sat on the edge of the bed. "I don't want that bitch around Damon any more than you do."

An agreeable silence settled between them as Elena digested Katherine's words. Both of them cared about Damon. Elena had known that, had even accepted it, on some level. But she would be lying if she said that the fact that Katherine still cared about Damon didn't scare her.

"It's always been about Katherine." Stefan's words reverberated in Elena's mind. Shaking her head, Elena told herself she was being ridiculous. Just because Stefan had chosen Katherine over her didn't mean that Damon would too.

Cocking her head to the side, Elena asked, "Are you sure you can help me? I'm assuming Klaus has compelled you not to kill her."

"I can't kill her. That's all I know." Flipping a few curls over her shoulder, Katherine sniffed. "And before you ask, yes you can trust me. This doesn't make us new BFFs or anything. I am helping you because I want Marissa gone. It has nothing to do with you really."

Smirking, Elena said, "I don't want to be friends, Katherine. I just need to know that I can trust you to carry out your end of the plan. For Damon."

Stiffening, Katherine scowled. "Someone's here." She flew to her feet just as Marissa appeared in the room within a rush of air.

"Well, it's nice to know that you can't kill me, Katherine." Marissa grinned triumphantly. "That will make this easier."

Elena gasped as Katherine blurred to stand in front of Marissa. "I might not be able to kill you, but I am still stronger and faster than you are. And I will enjoy hurting you." And then she stabbed Marissa in the stomach with a letter opener she'd grabbed from the bedside table.

"You underestimate my threshold for pain." Marissa licked her lips as she yanked the piece of metal from her chest. "You see, I enjoy pain more than most." She raked the letter opener down her arm, slicing her skin open. "In fact, it turns me on. So bring it on."

"You're not getting anywhere near Elena." Katherine grabbed Marissa's arm as she tried to stab her.

"Why not?" Marissa sneered. "Think about it, Kat. With her out of the picture, you wouldn't have to worry about Stefan ever getting back together with her."

"And let you have Damon? I don't think so."

Elena watched Marissa's eyes narrow on Katherine. "You still love him. And now I am pissed." She kicked Katherine's feet out from under her, but Katherine recovered before she touched the floor.

Katherine flung Marissa against the wall. "Elena get out of here!"

Without hesitation Elena ran to the door only to have it slam in her face. Gripping the handle, she found it locked. But how could that be? It was supposed to lock from the inside. When she tried to turn the lock, it wouldn't budge.

"Elena!" Alaric's muffled voice sounded from the other side of the door. "What's going on?"

"Ric!" Elena screamed as Marissa snagged her by a handful of hair. "Call Damon!"

"I don't think so bitch!" Swinging a heavy brass candlestick, Katherine knocked Marissa away from Elena, who backed into the corner.

Popping her shoulder back into place, Marissa cackled in delight. "You can't win this one Katherine. You said yourself that you can't kill me. Just give it up. Think about it. We can team up. You can have Stefan; I'll take Damon. Think of the fun we'd have."

"There's one problem with that plan, Marissa." Katherine inched toward the bookshelf. "Klaus will kill you if you kill Elena. And then I'll have both of the Salvatores for myself." Katherine pulled a book from the shelf and snatched a wooden stake that was hidden within it. Growling, Katherine launched herself at Marissa, thrusting the stake into her stomach.

"Ooh." Marissa hissed as she plucked the stake from her shoulder and expertly threw it into Katherine's chest. As Katherine crumpled to the floor, Marissa turned to face Elena. "Time to say goodbye Elena."

Standing on shaky legs, Elena faced Marissa. "You do realize that if you kill me Damon will never forgive you right?"

She shrugged. "It will take him a little while, but he will eventually get over it. He always does. You wouldn't be the first lover of his I've killed." As she stepped closer to Elena, excitement flashed in her brilliant green eyes. "Anyway, it will be worth it just to see Damon and Stefan no longer fighting over you. Goodbye Elena."

This was it. It was time to see if Bonnie was right about her necklace. And if the necklace didn't save her, then the joke was on Marissa. Stefan's blood was still fully in Elena's system.

A sickening sucking sound filled the air and Elena watched in horror as Marissa's head tumbled from her body and landed on the floor with a sickening thump. The floor tilted and Elena's legs collapsed. Strong arms caught her and carried her to the bed as white dots blurred her vision.

"There you go love. You're okay."