Author's Note: I haven't watched Chicago Fire in a while so I want to apologize beforehand if there are any details left out. I'm going to try my best to keep the actual characters "in character" as much as I can. I might change a few things to make my story flow better, but it will mostly stick to the storyline of the original show. I'll try my best to make my original character as interesting and likable as I can!

These are the main things you should know before reading:

-Rose is Jay's younger sister

-Gabby is a paramedic at a different firehouse, which explains why there was an open space for Rose

-this story starts at the beginning of Season 2 of Chicago Fire

-there will be some crossovers from Chicago P.D. and possibly Chicago Med

So this is a story involving an OC who will potentially have an ending with either Severide or Clarke. Please review and keep reviewing as I update more chapters so I can use your input on pairings. Thanks! I hope you like this first chapter.

Chapter 1 - Spur of the Moment

"Jesus," Jay exclaimed. "Just answer the phone already or turn it off."

He knew he should be more gentle with his sister knowing that she was going through a breakup, but he had known from the beginning that Rose and Kelly wouldn't last long. He had heard things about the guy. He was known as the one firefighter who surrounded himself with a different woman every month. Of course that was an exaggeration, but that didn't stop him from believing that Kelly Severide was incapable of being in a relationship. Jay wanted the best for his baby sister and in his opinion, Kelly wasn't the right guy for her. But who was he to judge? He hadn't been in a long lasting relationship in a while.

"All right. I'm turning it off," Rose said as she finally silenced her phone and placed it onto the table with the screen down. "I just- I'm so tempted to pick up, you know? But I shouldn't. That'll just make things more complicated."

"Although I don't really like the guy, shouldn't you at least talk to him? He definitely shouldn't have started a relationship so soon with you after his breakup, but it's not like he cheated on you like…" he trailed off.

"Like Nathan did?" she finished for him.

Jay gave her a silent nod. He hadn't planned on bringing up her bastard ex-boyfriend but sometimes he spoke without thinking.

Rose's mind began remembering Nathan, her first serious boyfriend. She had met him when she was twenty and she had believed he was the one. She had even lost her virginity to him. The two had dated for four long years until she found out that he was cheating on her. After a total of three years of being single and untrusting of guys, she changed her mind and got involved in a relationship. She had moved back to Illinois a year ago after living in New York for a few years. Luckily, she was able to find a job quickly at Chief Boden's firehouse. While working there, she became accustomed to Kelly's friendliness and even found herself being attracted to the charming man. Eventually after his breakup with Renee, the two had somehow gotten involved in a relationship. They had seemed extremely happy together and no one at the firehouse could imagine them splitting up, but when his ex-girlfriend suddenly returned looking very pregnant with his baby, this all changed. And that was what led to Kelly and Rose's breakup after a few months of dating.

"Are you… Okay?" Jay asked. "You know, with what happened…"

Rose nodded. "I'm a little heartbroken, but Kelly is still a good guy. I want to end things with him on good terms... So I guess you're right. I should talk to him instead of ignoring him. It's not really his fault. I mean, he didn't know she was pregnant."

"So what you're saying is that you still want to be with him, but you're letting him go only because his ex-girlfriend is pregnant and you think they should be together?" Jay summed up her words.

Rose slowly nodded. "I admit, Kelly and I did have a connection, but the reason why he and his ex broke up was because she was moving to a different country and not for other reasons. Since she's pregnant with his baby and she has decided to come back, I shouldn't be standing in the way between them. I know that he loved her, or still loves her." She frowned not knowing whether to use past or present tense. "I need to move on."

Jay agreed with her. It was a good idea for Rose to end things with Kelly and let him return to his previous girlfriend. She was pregnant and the two still had a chance of raising the baby together. Rose had been hurt by a man before, she didn't need to endure more pain by staying with Kelly.

Rose glanced at her brother's face. "I can see the worry in your eyes. Stop worrying about me. I'm a big girl now." She winked as she said the last part attempting to lighten up the mood.

"Yeah, but you're still a baby to me," he said as he pinched her cheek, something she hated since childhood. Was there anyone out there who didn't hate it?

"Ow!" she yelped as she instinctively reached up to rub the pain away with her hand.

Jay let out a snicker before looking down at his phone to see what time it was. "Listen, I uh, I've got to get going," he said as he put his phone into his pocket. "I have some undercover work to do. You want me to drive you home or are you gonna call a cab?"

"I'll… Um, I'll work something out," she responded.

Jay sighed. "Just be careful, okay? Don't drink more than you should." He knew that his sister had a low tolerance for alcohol so she didn't drink enough to actually get drunk, but that didn't mean he didn't have to be concerned.

She nodded with an assuring smile. "I won't! You know how boring and responsible I am," she joked. "Stop lecturing me and go and do your detective work, bro."

He laughed. "All right, Rose. I'll see you soon. Oh, and if you happen to see me around in the next few weeks, don't blow my cover."

"I know. I know," she said. "You've reminded me this so many times before."

After Jay left the bar, different men began approaching her trying to start up a conversation. It made her realize how much of a difference Jay's presence made. To her, he was just her annoying but awesome brother, but to others, he was someone different.

She heard someone sitting next to her and she was prepared to tell them she wasn't interested for the sixth time when she realized that she knew this person. He had a hairstyle generally known as a military cut and that familiar stoic but calm aura radiated off of him. Even if he seemed mysterious, his gentle looking face and big blue eyes prevented her from being intimidated by him. She hadn't heard much about him because no one at the firehouse knew, but she had a feeling that he had served in the military before becoming a firefighter. There was just something about him, something similar to her brother Jay who had also served.

She was surprised and felt like a deer caught in headlights when he suddenly turned his head over to her.

"Rose, right?" his voice was on the deeper side and she admired the smoothness of it.

She quickly recomposed herself. "Yes, that's me." She began searching through her brain to remember his name but she just couldn't. Maybe she would have remembered it if she hadn't been so concerned about her issues with Kelly.

"Jeff," he said out of nowhere. "That's my name."

"Right, Jeff. Sorry," she blushed. "I'm usually good with names. I just have a lot on my mind at the moment."

"I completely understand," he said as he ordered a drink. "So... Do you want to talk about it?"

She didn't know why, but the way he looked at her made her want to unravel everything in front of him. She needed someone to talk to. Someone who didn't know about her and her relationship with Kelly already, someone unbiased. Jeff was the perfect person to talk to.

She took a sip out of her glass before placing it back onto the table. "Actually, yeah. If you're okay with it."

"I'm here to listen," he encouraged.

They reached the entrance of her home. "Thanks for tonight and uh, for bringing me home," she said with a grateful smile. "I really needed that. I mean, having someone to talk to."

"It's not a problem at all." He returned a smile.

"Can I ask you something?" She took his silence as a yes. "So why did you decide to come to the bar tonight?"

His smile tensed at her question. "It's just a bit complicated..." he simply said.

His short answer was enough for her to know that he didn't want to talk about it. It felt strange to know that she still had no idea who Jeff Clarke was, but he knew a few things about her since she had told him about herself at the bar. She could tell he was a nice man and charming too, but he was just too hard to figure out. She hoped that the next time they had a night out, she could have him tell her what was on her mind.

She nodded in understanding at his vague explanation.

He gave her a polite smile. "I'll see you tomorrow then?"

"Wait, Jeff." She didn't know what took over her, but she stepped closer to him and rose onto the tips of her toes because even with her heels on he was so much taller than her. She pressed her lips onto his while closing her eyes. Without a second of hesitation she felt Jeff responding to the kiss, his lips soft but firm against hers. When the two pulled back, she was slightly breathless. "Will you stay the night?"

He didn't answer her with words. Instead, he leaned down and gave her another kiss.

Minutes later, the two found themselves in the bedroom of the Chicago two flat she lived in. It was clean and well organized. In the back of Rose's head came the thought that the only man she had ever invited into her new place other than her brother was Kelly. She pushed away the reminder. She wanted to forget about him. She wanted to move on. This was crazy, but she liked Jeff. A lot. She liked how he was genuine and gentlemanly with her. She briefly wondered if she was being selfish only wanting this because she wanted to forget about Kelly, but Jeff didn't seem to mind. He wanted her too, didn't he?

But what about Kelly? What would he think if he found out?

Rose reminded herself that she had clearly told him that she wanted to end things with him. The two had broken up. She wasn't doing anything wrong by sleeping with Jeff.

"Are you sure about this?"

She nodded in response to Jeff's question. "I'm sure. I want this. I want you. To be honest, I've never done this before. I've never invited a man into my place to have sex on the first date." She bit her lip as she said so.

She was telling the truth. She didn't normally do spontaneous or crazy things. This was totally out of the norm for her. She didn't exactly know what to make of it.

"So this was a date?" he asked.

Her cheeks reddened in embarrassment. "I don't-I mean-I-"

"I'm just teasing you," he interrupted with a grin. "If you're all right with it... Let's call tonight our first date."

"Sounds good," she let out in a shaky breath. The stubble on his face tickled her as his lips gently kissed her neck. Her skin felt extra sensitive and she experienced pure bliss under his touch.