A/N - I have 90% of this fic written already and I'm working my way through proof-reading the chapters. There may be a few published at once (depending on length), or each week, so please do fav the story to receive new chapter notifications.

This first chapter is set towards the end of S15 with a flashback section from S11E21.

Chapter One

The cold February air stung at my cheeks as I stood in front of the building I'd not set foot in for four years. I'd forgotten what Chicago winters felt like. The layers and layers of clothes it took to keep the cold out, looking like you were out on an Arctic expedition, and then instantly losing twenty pounds when you got to your destination. I was ill prepared for the temperatures of February in Chicago. Having previously lived here, you'd think I would know better. I've clearly gotten used to San Francisco weather

Standing here again after all these years was jarring. I'd told myself earlier in the day that I was going to come. I'd convinced myself I was ready to come back. My heart was beating out of my chest and the cold was soon replaced by the wave of heat rising to my head. Then came the breathlessness. It had been a while since I'd felt the physical manifestations of the anxiety that had haunted me for so many years. But it wasn't the building that made me feel anxious, it was the memories that this building held for me. Some good, some bad. And some incredibly painful. Today was a significant day and one I would never forget. Because nine years ago, my life almost ended here.

Lucy Knight stood looking at the entrance of the ER at County General in Chicago. She'd left four years ago and hadn't stepped foot in Chicago, let alone County, since then. Lucy had been stabbed by a patient on Valentine's Day 2000 along with her colleague, John Carter. She'd been a fourth-year med student at the time and her injuries were so severe, she wasn't expected to live. If it hadn't been for the tireless efforts of her colleagues, she wouldn't have.

She was lucky to be alive, lucky to have the life she had now; a successful, and well-respected emergency physician. She was published, running her own ER, and trying to help improve ER services throughout the country. She was, in fact, in Chicago for a hospital management conference talking about the changes she'd made at her level one trauma center at San Francisco General Hospital. She took a deep breath and walked through those familiar doors.

How was it that hospitals always had the same smell? There had been a few changes on the surface that she could see. There was a security guard posted in the waiting room, secure doors to get through to Admit. Beyond she could she the desk with unfamiliar faces milling around. Sat on the other side of the triage window was a face she recognised instantly. It wasn't a surprise she was still here.

"Take a seat. I'll get to you when I can." Haleh was concentrating on a chart she was writing on.

"I need to see a doctor."

Haleh smiled as she recognised the voice on the other side, dropping her pen. "Oh my god. Lucy, is that you?" She pressed the button to open the door to let Lucy in and enveloped her into a hug. "Why has it taken you four years to come visit?" She chastised Lucy and held her out at arms' length to look at her fully.

"I'm not surprised you're still here." She hugged the nurse with affection.

"I'm part of the décor now." She joked and then went serious. "And I still haven't forgiven you for not saying goodbye."

"Lucy looked at her sadly. She had regrets about the way she left, but she hadn't been in a good place emotionally at the time. "I know. I haven't really forgiven myself either."

She was talking to Haleh as they walked over to Admit when someone bumped into her. She turned to apologise and came face to face with Carter. He was the last person she'd expected to see. She felt all flustered and struggled to formulate any words, finally realising she was just staring at him with her mouth open, but thankfully he looked as shocked as she did.

All he could say was "Lucy", then remembered he'd bumped into her. "Sorry about that. I wasn't paying attention."

"That's ok." Things felt awkward. But it wasn't surprising with how they'd left things. After all, he was the primary reason she'd decided to leave County and head home to San Francisco. They stood awkwardly for a moment in silence while Haleh quietly stepped away. "It's good to see you." The familiar butterflies returned to her stomach. She didn't actually know if it was good or not, but she had to break the awkwardness somehow.

Carter was taken aback by seeing Lucy. She'd been on his mind all day, as she always was on that day every year. It had been four years since he'd been able to talk to her, to see her. She looked exactly the same as she had back then. He traced his eyes over her face, studying every single inch. She looked happy and healthy, if a little shocked at seeing him. But the feeling was definitely mutual. He closed the gap between them and wrapped his arms around her, pulling her body closer to his. "What are you doing here?" He inhaled her scent as he did. It felt comfortable. Natural. He thought back to the last time he saw her and the last time he held her in his arms.

Carter had returned from Paris having decided he was going to try and make it work with Kem. Disappearing to Paris so impulsively probably wasn't the best of ideas, especially as he was still with Lucy at that point. Although, she'd been pulling away from him more and more, making him think it was already over.

Why was his life so complicated? He loved Lucy more than anything, but he loved Kem as well, and if Lucy had had enough of him, then he owed it to Kem to try and save their relationship. It had been a difficult decision to leave Chicago for good, but that was the sacrifice he had to make.

Upon returning to Chicago, Lucy had barely said a word to him, keeping it strictly professional. In a way he was glad he was leaving; he couldn't work like this with her any longer. He knew she had a reason to be angry at him, but she was the one who seemed like she didn't want to be with him anymore. He just hoped she would understand why he was leaving and that they could still have a friendship once she calmed down.

Carter's last shift had rolled around, and the staff were going to gather in Ike's for some farewell drinks. Lucy had managed to avoid him for most of the shift again. He'd heard rumors she'd withdrawn her application for chief resident, but no one seemed to know anything more than that, and she hadn't said anything to anyone as far as he knew.

When he walked through the doors of Ike's after his shift, there was already a group congregating in the corner talking animatedly. As he approached, Lucy's name was mentioned, and he was shocked by what was said.

"What did you say about Lucy? She's leaving?" Checking he'd heard right.

"Yeah. She's moving back to San Francisco. Got a Fellowship at UCSF apparently." Chuny told him what she'd heard. "It was her last day today."

"Today?" Carter couldn't believe what he was hearing.

"Yeah. I heard she withdrew her chief resident application weeks ago. I can't believe she didn't tell anyone." Abby sounded hurt.

"She wanted to leave quietly I guess." Haleh supposed.

Carter was listening trying to process what he was hearing. She had to have applied for that fellowship months ago, while they were still together. Is that why she'd pulled away? Because she'd already decided to end it?

"Why didn't she come here tonight? We could've had a joint send off." Luka wondered.

"I saw her on her way out and suggested it, but she's leaving tonight?" Chuny said.

Carter jumped up from his seat. "I gotta go." He darted out of the door.

"She's probably already left." Chuny called after him, but he was already out of the door.

Carter grabbed a taxi hoping he would make it in time. Pulling up outside of her apartment building, he saw her just getting into a taxi. "Lucy!" He called out, trying to get her attention while throwing twenty dollars at his driver. She looked over in the direction her name came from, and her expression changed when she realised who it was. "Wait!...You're going to leave without a word? No goodbye? Nothing?"

"What's left to say?" Lucy's fight was gone, her energy for their relationship drained.

"How about you applying for UCSF when we were still together!" He was so angry at her.

"Barely." She said sadly.

"Barely, what?"

"Barely together."

"Only because you clearly had other plans. You were plotting the demise of our relationship that whole time. It explains everything now!" He was having a hard time keeping his anger at bay. He felt so hurt.

"I wasn't plotting our demise, John. I was preparing for when you inevitably broke my heart. Again." She exploded at him, not believing he had the nerve after leaving her like he did.

Her words cut deep. Is that what she had been thinking? It hurt that she had felt that way, though it was obviously what had happened in the end.

"You coming? The meter's running, you know?" The taxi driver was getting impatient, but also engrossed in what was happening with his passenger.

Carter angrily took out a twenty from his wallet and threw it at the driver. "Here. Give us a minute." Seemingly satisfied, the driver turned back to the front, continuing to listen.

"You don't get to be angry here, Carter. I do. It feels like you used me. I understand you needed someone after Joshua, and I was happy to be there for you as a friend. But you always end up wanting more from me. And against my better judgement, I let you."

He was barely listening, unable to move past what she said before. "Why did you think I was going to break your heart again?"

"Because that's what always happens with you. You never know what you want. So, this time, I didn't let myself get too attached. And it turned out I was right all along. I can't be here anymore. This city has too many ghosts for me now and I can never be happy here."

"I'm sorry I make you feel like that." He was truly sorry. "I never set out to hurt you, but somehow, I always do. I didn't even know what I wanted." He sighed heavily. "But I feel like I owe it to Kem to try again."

He started rambling. "But. Then I'm so drawn to you Lucy. You have so much power over me, that sometimes I feel like I can't think straight. You drive me crazy at times, but I always find myself coming back to you." He knew every inch of her face. The way her eye would twitch slightly when she was angry. The way they glistened when she was trying not to cry. He could see that in her face right now and it killed him that he was the one causing her to feel like this. He wanted to take the anger and pain away.

They stood there in silence for a moment searching each other's eyes. Deciding what to say next. He impulsively took her face in his hands, pulling her in and kissing her deeply on the lips. He hadn't intended on doing it. It just happened and he couldn't stop himself. Didn't want to stop himself. Everything was such a mess. "I'm sorry...I'm just...I'm so conflicted right now."

Lucy gathered herself. She hadn't been expecting him to kiss her. "Then let me make this easy for you." She spoke softly, but the words clearly hurt to say. "Forget about me, John. Go back to Kem. I understand. I do. All I want for you is to be happy. It's all I've ever wanted, even if it isn't with me." A tear escaped and rolled down her cheek.

Lucy's words were like a punch to the gut. They didn't have the desired effect on him. He felt like he loved her more than he ever had in that moment. But he couldn't escape feeling like he had an obligation to Kem. He gently wiped the tear from her cheek with his thumb. He needed to tell her one last time.

"Don't say it." Lucy could sense what he was about to say. She knew him too well. "Don't make this harder than it already is."

"You know I do."

"I do too."

"Good luck, Luce. Chicago will always be a little greyer without you here. You're gonna do great things in San Francisco. They're lucky to have you." He enveloped her into a hug that lingered longer than it probably should have. "I'll call you soon. You can tell me how it compares to County."

Lucy pulled away. "I…I can't have you in my life anymore, John. It hurts too much."

"But…" He couldn't believe what she was saying.

She got into the taxi before he could say anything else. "Goodbye, John." She closed the door without another word and the taxi pulled away leaving him stood there in shock.

Had she just said goodbye to him for good? He had assumed they would always be in each other's lives. Selfishly expecting her to be there if things didn't work out with Kem. The realization of what had just happened overwhelmed him. He had to bend over and lean on his legs, his emotions becoming too much. He couldn't imagine a life that didn't have Lucy in it. He didn't want to imagine it.

Once he was able to compose himself, he waved a taxi down and headed back to Ike's to find that most of the party goers had left. Only an orderly remained as he looked around in confusion.

"Everyone had to leave. They were paged back to the ER."

He stared at the slideshow of pictures. A picture of Lucy and him all smiles from one Christmas appeared and the gut punch returned. This leaving party really had taken a turn for the worse.

"I've been at a management conference for a few days. It'd be rude to come to Chicago and not say hi." She explained. "What are you doing here? I thought you were still in Africa!"

"I'm back for a while. The new center opens soon, so I needed to come back and deal with some of the logistics to do with that. I'm just locumming while I'm here."

"The center. Right. That's such great news."

"Yeah. It's been stressful, but worth it...So, chief of the ER, huh! Impressive." He'd read a few of her research articles while browsing the journals over the years and he'd looked her up.

She blushed which brought a smile to his face.

Attendings, Simon Brenner and Archie Morris, walked into Admit discussing a patient. Simon looked over and noticed Carter hugging someone. There was a familiarity in the way they hugged. When they parted, he was able to see the recipient. She was short, a lot shorter than Carter. Her blonde hair was pulled up into a bun and the suit she was wearing was fitted and showed off her petite frame. He couldn't take his eyes off her.

Morris was still rambling away, not noticing Simon was otherwise distracted. "Who's the blonde talking to Carter?" He figured Morris might know given he'd been there a lot longer.

"Huh?" Morris looked up to where Carter was standing to see who Simon was talking about. "Well, I'll be damned." He didn't even answer Simon before he went over to them. "Lucy Knight. What are you doing here?"

Lucy and Carter were talking when she heard a familiar voice, and before she knew it, she was being enveloped into another hug. "It's good to see you." He was genuinely happy to see her.

"Hi Morris. I've been at a management conference. Thought I'd check in."

"Wow. That sounds like a snore fest." Morris screwed up his nose.

"I was the keynote speaker!" Lucy watched him squirm as he realised.

"Oh. I didn't mean you're boring. I just...meant that management in general..uh, can be boring. I mean..." He stumbled over his words in embarrassment.

Lucy burst out laughing "Stop Morris. It's ok. They are boring. They just happen to be part of my job."

Carter laughed as well but was watching Lucy closely. He loved the way her face lit up when she laughed. The way her eyes crinkled at the edges and how blue they were. He thought be remembered the color of her eyes but his memory didn't do them justice. He felt that familiar ache return to his chest. It had been so long, he'd forgotten what it felt like. He'd got so used to not speaking to her, the feeling was a little jarring.

Back at Admit, Simon was still none the wiser to who she was. He was lost in his thoughts when he heard his name.

"Dr Brenner! Simon!" Tracy Martin, an intern, was standing next to him trying to get him to sign a chart, but he looked to be staring off into the distance. "Can you sign off on this please?"

Simon took the chart from her, and Tracy looked over to where he had been staring so intently. "Who's that Carter and Morris are speaking to?" She asked.

"I heard Morris say Lucy Knight. Must be someone who worked here."

"An ex of Carter's." Tracy guessed.

"Really? You think?"

"Look at the way they're stood together. Their body language." Tracy studied them. "Ten dollars they used to date."

"You're on." He looked around to find someone who'd been around longer than them when he spotted Sam. "Hey, Sam." Simon tried to grab the nurse's attention as she came out of exam two. "That woman with Carter and Morris. Did she and Carter date?"

Sam looked up from her chart and saw Carter stood with Morris and Lucy. "Lucy? Yeah, they did. Didn't end so well though."

"See. Now pay up!" Tracy was holding out her hand to him.

Simon rolled his eyes and got the money out to pay her. Tracy was looking very satisfied with herself.

"Did you two make a bet?" Sam enquired.

"Yep. I said they'd dated. Simon questioned my skills. And he's now ten dollars lighter." She was diligently inspecting the note.

Sam just shook her head. "Here. How about stop staring and do some work" She forced the chart into Simon's hands and went over to say hi to Lucy.

Word spread of Lucy's return and many of the other staff she knew were coming to say hi and find out what she was up to. Lucy had been hugged so much, she thought she might have bruising to her ribs. Eventually people filtered away to resume their duties leaving just the three of them again.

"The three of us should go out to dinner tonight. We can catch up." Morris said enthusiastically.

"Sorry, Morris. I've got a flight in a few hours. I'm back on in the morning."

"No rest for the wicked!" He mused.

"Nope."

"Well, I should probably get back to work." Morris gave her another hug. "Don't leave it so long next time."

"I won't."

"I'm just about to take a break. Got time for a coffee?" Carter asked.

She looked at her watch knowing she did have time, but unsure if she should accept. Seeing him again was stirring up feelings she'd long buried. She'd been telling herself she was over him, but it was a lie, she had merely learned to live with it. Not having any contact with him made it a lot easier. But she had missed him. Missed his friendship. Against her better judgement, she threw caution to the wind. "Yeah. I do."

Carter and Lucy headed over to the Jumbo Mart and took a spot by the window, holding their hot coffees tight in their cold hands.

"It still feels weird this being here." Lucy mused as she took in the surroundings.

"You get used to it...I gather from your reception you haven't been back?"

"No. This is my first time back to Chicago, let alone County. Too many memories." She said, trying to keep her voice light.

Carter had always been so good at reading her, but he was having trouble. Four years apart will do that. "I'm sorry."

"Don't do that. It's fine. I'm not the same person I was four years ago. The past is the past, let's leave it there." Lucy really didn't want to open old wounds, she was having a hard enough time just seeing him.

"So, keynote speaker. Pretty big deal." He changed the subject, not wanting to press anything. Lucy just shrugged her shoulders and murmured. "Come on, Luce. You always do that. Don't downplay your achievements like that."

Lucy hated being called out, but he was right. "It doesn't matter how many times I do it, I still hate presentations. Get me in a classroom in front of a hundred med students over that any day…So. How long have you been back?" She quickly changed the subject, to take the attention away from her.

"Only a week. It's been...an adjustment."

"I can imagine. A lot of things will have changed. I bet it's weird having labs and equipment again."

"That and feeling like a fish out of water. It'll take some time, but I'll get used to it again."

"How's the center going?" Lucy took a sip of her coffee.

"It's almost finished. There's going to be an opening ceremony early April…" Should he say it? "You should come." Too late! Was it going to be too difficult? He caught her expression changing when he asked. Maybe it wasn't a good idea they see each other again, but he really did want to see her again. "If it wasn't for you, this center might not exist."

Lucy looked at him in confusion. She had no idea what he was talking about.

"The idea started with you. You were there. You know I wasn't dealing with Joshua's death very well. But you said to me, rather than staying angry at the world, I should do something to help it. I should channel my grief into something positive. So, I did."

Lucy had forgotten she'd said that to him. It had killed her to see him so broken, knowing she couldn't do or say anything that could help his pain. She'd said it one day during a particularly low point for him to try and give him something else to focus on because he was starting to spiral, and she was scared of what was going to happen to him. After that, he slowly emerged from his dark hole. Less angry at the world. Less angry at her. But it also marked the beginning of the end for them. Again.

She wasn't sure it was entirely the smartest idea to see him again. But she did want to see the product of what she now knew she had set in motion. "If I can be there, I will." She promised. It occurred to her that she would most likely see Kem again which she wasn't looking forward to. She was curious. "How's Kem? Is she in Chicago as well?"

"Erm. She's good. She's not here yet. Too busy with work to get away. She'll be coming over for the opening." Why didn't he just tell her the truth? They were pretty much over. They'd tried again when he left but never really recovered. He hadn't even told Kem the real reason he was back in Chicago. "What about you? You married?" He wasn't sure he wanted to know the answer either way.

"Nope. I'm too busy for relationships. Closest thing I have to a husband is Dave." She laughed.

"Malucci?" He couldn't hide the surprise in his voice. "You're still friends?"

"Yes. We're still friends, and we work together." Lucy could hear the surprise in

his voice. "I know you never liked him, but he's matured. He's a good man once you

scratch the surface." She paused, getting sentimental. "He's been the one constant in my life."

Her friendship with Dave had always bugged him and his jealousy had played a part in why their relationship failed. He had been wary of Dave Malucci and his womanizing ways, but he'd also been foolish for not trusting Lucy when she told him they were just friends. He wondered if they were still just friends.

Lucy could see the cogs turning in his head. "Dave and I have never, and will never, ever, be anything more than friends!" She looked at him with raised eyebrows hoping he finally got the message.

"I wasn't…Never mind...So, are we going to address the elephant in the room here, or…?"

"Happy anniversary." She said nonchalantly, smiling as she did.

Carter wasn't sure how to react to that. He'd never heard her joke about it like that before and his expression obviously showed this because she thought he didn't approve.

"Come on Carter. You're a doctor. Having a morbid sense of humor is mandatory."

"It's not that." She seemed so different. "I've just never heard you joke about it like that before."

"Like I said, I'm not the same person I was back then…I should go and grab a taxi." Lucy looked at the time and downed the rest of her coffee. They walked outside together, bracing against the sudden cold that hit them.

"So…" He didn't know what to say, or whether or not to hug her, but she moved in to hug him first.

It was hard seeing him again. She felt so drawn to him. Every time they were close, it was like a magnet drew them closer still. Twenty minutes wasn't enough, and it was hard to leave now. She stared at him as he flagged a cab for her. His nose and cheeks already red from the bitter wind, and his hair blowing around. Her heart let out a cry of longing. He opened the door for her and as she got in, their bodies brushed against each other. Her head was spinning, and she needed to get out of there before she acted on impulse, desperately wanting to kiss him. "Maybe see you in April." She said as he closed the door and the cab drove away. She sank into the seat and let out a sigh. The cab driver was talking to her, but she hadn't been paying attention. "Huh?"

"Where to?"

"Oh. Sorry. O'Hare please."

Carter watched her drive away and he knew his life just got complicated again. He sighed heavily wondering if he would see her again.