A strange feeling washed over Caroline as she walked into her office. She couldn't identify it at first but it was oddly familiar. Like a song you hear on the radio that you know you've heard before but you can't quite sing along. Whatever it was, it stirred something inside her heart, something she'd long thought impossible, and she didn't understand why.

Then his scent hit her and it all flooded in. Her heart was racing, her breath caught in her throat. She froze mid step; it was like she'd been instantly transported 15 years back in time, back to that day in the woods, as if nothing had changed since then. The effect he had on her hadn't lost it's power over the years.

Caroline turned around slowly to verify that he was really there. Her whole body went numb when her eyes landed on him, leaning against the wall, arms crossed.

"Klaus," she breathed with disbelief.

"Hello, Caroline," he smirked. She was again overwhelmed with memories of the last time she'd heard those words.

"What...how..?" she struggled to form her question. What could she possibly even say to him? It'd been 15 years since he'd promised her that he was never coming back and in return she'd given him the truth. She told him she was building a life for herself and now that she had, did he think he could just walk into it?

"What are you doing here?" she finally demanded. The smirk slowly faded from Klaus' face.

"I need your help," he answered quietly. That floored her; she'd been expecting a grand gesture or a suggestive comment but the sadness in his eyes took her completely by surprise.

She opened her mouth to speak but soon found she was at a loss for words. Instead, she returned to her previous task of hanging up her purse and slipping into her lab coat. She sat down behind her desk and gestured towards the chair across from her.

"Maybe you should elaborate," she suggested.

Klaus hesitantly lowered into the blue armchair that usually seated Board Directors and patients.

"Well, first I have to ask.. After I left that day, did Tyler tell you..about Hayley?" he asked hesitantly.

How could she have forgotten? The news that had broken her heart into pieces, devastated her beyond belief. That Klaus and Hayley were going to have a baby. She had only figured that that's why he was so willing to leave her behind.

She tried to ignore the pain that was radiating inside her chest. How could that memory still hurt so much after all this time?

"Yes," she answered shakily.

"So you know I have a daughter?" he asked her directly, never taking his eyes off hers.

That shook her a bit. She simply cleared her throat and nodded, allowing him to continue.

"She's a werewolf, obviously, though she hasn't triggered the curse. Her blood has the ability to create hybrids, which I think means she can't become one. Her body rejects vampire blood," he explained.

The scientist in Caroline was instantly intrigued. She'd spent a lot of secret time in labs after hours studying vampire blood and DNA, both in med school and at the hospital. The thought had occurred to her time and time again that hybrid blood would be even more fascinating, but she'd never imagined she'd be able to get her hands on it. Now she might have the chance to see something new altogether, a one of a kind species; but she was getting ahead of herself.

"That's...interesting," she replied hesitantly. She was still waiting to hear why he needed her help.

Klaus took a ragged breath and Caroline saw the earlier sadness return to his eyes.

"She's sick," he whispered. "She's been having horrid hallucinations and she has these heart issues. I've been to cardiologists, I've talked to witches, I've tried injecting her with my blood. Nothing. She's dying,"

Caroline was both shocked and pained to see how tortured Klaus was over his daughter's health. He looked so sad and afraid she couldn't help but hurt for him. This was the man she knew, the one she'd always seen beneath the hard exterior. The man that felt and cared deeply for those around him, even if he had a hard time showing it.

She knew then why he was there, why he needed her help. She couldn't bring herself to make him come right out and say it; she knew this had been hard enough for him.

"Why didn't you come to me first?" she asked as she leaned back in her chair, studying his reaction. His eyes snapped up to meet hers in surprise.

"I didn't know at first. I tried to.. keep my distance, like I promised," he smirked a little, but it didn't meet his eyes. "After I'd exhausted the obvious options, I had people start looking for doctors who were aware of the supernatural. I was soon given the name of the best diagnostician in the country, whom was rumored to be a vampire," he finished, and the smirk had returned genuinely. Caroline blushed when she recognized a hint of pride in his expression.

"You can imagine my surprise. I was under the impression you had to be good at arithmetic to be a doctor," he joked.

Caroline laughed, remembering the way he'd teased her about her math skills. A pang shot through her heart for what seemed like the hundredth time since he'd first arrived.

She looked down and smiled. "Well, maybe you were just wrong about me, and what my strong suits are,"

When she looked back up, she expected to see him smiling, ready to return her banter. But he was staring at her solemnly, the exact way he had always looked at her, as if he were seeing straight into her soul. Her breath caught in her throat.

Klaus was the first to break the heavy silence, "Here, I have her medical file. A history from the doctors we've been to see,"

"Oh, great," Caroline smiled as she reached out to take it. Their fingers brushed in the exchange of the folder, sending chills throughout her body. When her eyes met Klaus' she could tell he was feeling the same effect and she couldn't help but smile.

She leaned back in her chair while she flipped open the file, trying to bite the grin off her face. It faded easily when she took in the medical information.

"This is impossible," she exclaimed in wonder, eyes narrowed as she flipped through the pages, trying to find something that she'd missed.

"Cardiogenic shock, but no-"

"No heart attack, yeah that's what the other doctors said too," Klaus finished for her, his voice resigned.

"No heart anything! No acute myocardial infarction, no Wolff-Parkinson-White disease. This is crazy..," she shook her head as she trailed off and Klaus watched with amused eyes. She was so different and yet so much the same.

"Do you guys still live in New Orleans?" she asked, eyes still narrowed toward the folder.

"Yes. We travel a lot but that is our home. Why?"

"It's still a hot spot for toxins after Katrina.. Travel where?" she insisted, grabbing a pen.

"Uh, recently, New York," he offered.

"What about out of the country?"

"Um, we went to England about 6 months ago,"

"Okay," Caroline nodded as she jotted down some notes. Her brain was whirling with ideas, trying to make sense of the medical mystery. Finally, she broke out of her reverie and looked up at Klaus.

"Where is your daughter?"

"Hope is with Rebekah," he smiled easily again.

"Rebekah, hmm," Caroline grinned and rolled her eyes. "There's a name I haven't heard in awhile," she said and Klaus laughed. "Anyway, bring her in. I'll do whatever it takes to help her," she promised, even though she knew it was a dangerous thing to do.

Klaus sighed in relief. "Thank you, Caroline,"

She smiled and then looked down, trying unsuccessfully to keep the blush from spreading over her cheeks. She knew she shouldn't ask, but she couldn't help herself.

"So, where's Hayley?" she asked hesitantly. She refused to look at him and the smirk she figured was plastered smugly on his face.

"She died," he answered quietly, causing Caroline's head to snap up in surprise. "In childbirth," he explained.

"Oh, I'm so sorry," Caroline sighed and desperately tried to convince herself that the weight lifting off her heart wasn't relief.

"It's alright, love. She was family, especially given her relationship with Elijah, but it's been a long time,"

Her relationship with Elijah.

Not relieved, not relieved, she told herself again. "Oh, Elijah. I assumed you guys were-" was all she managed to utter before he cut her off decidedly.

"No," he said. "No, my heart has only ever had room for one woman in that sense. I'm still waiting for her,"

Caroline's whole body erupted in fireworks and just like that, they were back.

Some things never change.