A/N: This prompt was brought to my attention by tumblr user halsteadsass and I had a really good time writing it! I debated whether breaking it down into a 2 shot, or leaving it as a very long one shot, I decided on the latter! So I hope everyone enjoys this little piece, and Trouble is a Friend should be updated later this weekend (but I'm rolling tomorrow night, so maybe not)! Anyways, I thrive off your reviews, it only takes a few words to brighten my day! -Mary

Jay Halstead was 17 years old, a senior in high school. He'd already decided he'd be enlisting in the military; set to be off to bootcamp a week after graduation.

Towards the beginning of his junior year, his friends, who he's been friends since grade school, started getting into some bad stuff. It started with going to parties every so often, and now, halfway through the first semester of their final year of high school, they were hitting the hard stuff almost every weekend. Ecstasy, cocaine, anything they could get their hands on they'd put inside their bodies.

Jay never really got into it. He'd known these guys for long, it felt strange not being around them- even when they weren't quite themselves. The group of teenagers had a bond that couldn't be broken. Jay was always around as their safety net, always making sure they didn't go to hard, and were safe.

"Halstead, you going to Jimbo's tonight?" Jay snapped his head up from his Trig homework at the mention of his surname.

"Yeah, but I have a family dinner thing, so I won't get there 'til late."

"Sweet dude, see you later!" Ian Wauters, he and Jay were never really the closest of friends, but growing up together, they knew each other pretty well.

It was already 11pm by the time Jay walked through the doors to Jimbo's apartment. Jimbo was a year older than everyone else, and had graduated last spring. He decided against college and lived in a tiny apartment with two roommates, throwing small "get togethers" every so often. Jay's group were always in attendance.

The place reeked of pot, and there was hardly any seating. The usual group of kids were there, only a few unfamiliar faces. He could tell everybody in the room was already completely fucked up. There were beer bottles everywhere, and a bong was being passed around the circle.

Taking in his surroundings, he noticed a girl he'd never seen before, her legs draped over Jimbo's. She looked younger than everyone else, between 14 and 16 years old. The only available seat was across from her, so he took it.

When the bong reached him, he declined, as usual, and again, he got shit for it. He has yet to tell anyone about enlisting; afraid of their reactions.

He took in the girl sitting on the opposite side of him. Her eyes were droopy and her skin was pale, but he could tell she was beautiful. He forced himself to unthink any thoughts about her though, because by the way she was all over Jimbo, it seemed they had a thing; and he didn't want any beg between him and Jimbo.

As the night went on, Jay couldn't keep his eyes off the brunette. She would pass out for a bit, wake up, drink more, then pass out again. He was drawn to her, but couldn't pinpoint why. Eventually, she and Jimbo went into the bedroom, and he took that as a cue to leave. Almost everyone, apart from himself, a boy named Reese, and Jay's best friend Bailey had left.

Jay hauled Reese and Bailey into his car and drove them back to his house. He knew the drill, and he knew their parents.

As he lay in bed that night, he couldn't get his mind off the young girl. He didn't want this life for her, and he was determined to help her out.

The following weekend, the gang decided to party at Jimbo's place again, and once again, mystery girl was there. It was strange because Jimbo didn't usually keep the same girl around for more than one weekend.

Jay began to get light headed from all the smoke in the room, and decided to go out on to the balcony get some fresh air. It was around 3am, and the only sounds from outside came from a bird every now and again. He leaned against the railing, nursing a beer when he heard the door slide open and out stumbled a very high mystery girl. Again, Jay had been watching her that night. She went hard, he saw her snort 2 lines of coke within an hour of each other, and even he had lost count of how many shots of vodka she'd poured down her throat. She immediately hunched over the edge of the balcony and emptied her stomach of the toxins she'd put it in only hours earlier.

Jay stood there, he wasn't sure what to do. Being who he was, of course he wanted to help her, he just didn't know how. So he performed the first action that came to mind. Setting down his beer, he walked over to her and used one hand to pull the hair out of her face. The other hand lightly rubbing her back as she vomited.

She was too fucked up to notice, but he didn't care. He wasn't doing it for him, he'd done this several times for his friends on various occasions, so it was nothing new for him.

After she finished vomiting, she stumbled backwards, into Jay, and he helped her slide down the wall into a sitting position. There was no seating outside, but Jay hoped the coolness of the pavement would ease her nausea. Her eyes shut tightly as she leaned her head against the wooden railing. "Stay here, I'm gonna get you some water." Jay told her once she seemed the least bit composed. She nodded in response, signaling she knew he was there.

When he returned, she seemed to be a little bit more sober than she was when he left. It did take him a while, as he wanted to make sure all of his friends were doing okay. "Here, drink this." He said, taking a seat on the floor next to her. She gratefully took the glass of water from his hand and surprisingly swallowed all of it in one, big, gulp. She handed the empty up back to him and rested her head on his shoulder.

She didn't know who this guy was, or why he was going out of her way to help her, but she liked it. No one had ever treated her like this before, usually when she partied, there wasn't anyone sober enough to care when someone got sick.

They sat in silence for a long while, until Jimbo roughly slid the glass open. Jimbo was an angry drunk, especially when he got too drunk, and tonight happened to be one of those nights. "Erin? What the hell?" He yelled, seeing Jay and Erin out on the patio. "Never thought you'd be the type of guy to steal another dude's girl, man." Jimbo sneered, directing his harsh words to Jay.

Suddenly, the previously drowsy Erin, was fully awake, "Who said I was your girl?" she barked at Jimbo, standing from her place next to Jay. "Not like anything fucking happened anyway. He was just being nice." She pushed past him and made her way back into the living room.

Upon Erin's walking away, Jimbo tore his angry gaze away from Jay and followed her into the apartment. Afraid of what was about to go down, Jay was right behind him. "And where do you think you're going?" Jimbo demanded when he saw Erin collecting her things.

"Away from you!" She yelled back at him. She was on her way out of the apartment when Jimbo forcefully grabbed her forearm and turned her to face him.

Everyone stood up at Jimbo's action, even the ones completely wasted. Jimbo and Erin stared at each other for a minute before Erin ripped her arm from his hold and walked out of the apartment. The entire room went silent, and one by one, everybody left. "That wasn't cool, man." Nate, another of Jay's friends said to Jimbo on his way out.

Jay was among the first ones to leave, with Ian, Bailey, and Reese, as he was their ride home. Ian and Reese were sober enough to go home, but Bailey was passed out in his backseat, so Jay opted to bring him to his house. He turned a corner on his way to his place after dropping Ian off; it was only a few blocks from Jimbo's, and saw a figure sitting on the curb. As he got closer, he realized the figure was Erin, so he pulled up next to her. "Want a ride?" He asked through his rolled down window.

Erin looked up, her face stained from tears, "I don't have anywhere to go." She said in a shaky, quiet, voice.

He opened the passenger door for her, "Get in." Erin didn't know why, but she obliged. She trusted this boy for some reason, and she didn't even know his name.

"I'm Jay, by the way." Jay stated, glancing over at her.

Her head was resting on the window, her hands in her lap. "Erin, but I think you already knew that." She replied with a raspy laugh.

Jay never responded, the rest of the car ride was filled with a comfortable silence.

"Aren't your parents gonna be mad that you're bringing some random girl home?" Erin asked as Jay pulled into his driveway and turned off his car.

Jay shrugged, "They trust me."

After Jay had Bailey settled on the couch for the night, he turned to Erin, "You can sleep in my bed, I'll get you some clothes; follow me." He went down the hall and opened a door to reveal a neat and tidy bedroom. He pulled open one of the drawers of his dresser and grabbed a pair of sweatpants, then into his closet and took a t-shirt, and handed him to her.

Erin looked at the clothes in her hand, "Where are you gonna sleep?" She asked.

Jay hadn't thought about that, he never usually gave away his bed. "Uh, I guess the floor."

"Don't be stupid, you can sleep in your bed, Jay. I won't bite."

They woke up the next morning cuddled into one another, but neither of them thought anything of it; it was cold outside and the warmth of each other's bodies was comforting.

"Um, thank you, for last night." Erin said as she prepared to leave. Jay offered her breakfast, but she declined, her thoughts drifting to her mother, and if she was okay.

"It's no big deal." He reached for a pencil and piece of paper, "Here's my number. You ever need me, for anything, you call me. Got it?"

Erin smiled the first smile he'd seen from her and took the slip of paper. "Sure thing."

No one in the group contacted Jimbo after that night. They saw something in him they'd never seen before, and truth be told, it scared them shitless. Erin though, the crew really liked her, and she started hanging around more often. She'd be at the same parties, she hung with the same kind of crowd that Jay's friends did.

There would be nights when she'd go home with Jay and he'd take care of her, and there were nights when she would find a guy to cling to and sleep with. It mostly depended on what she was on.

Over the course of 6 months, Jay became her rock. He would always be there for her, no matter what. It was the end of April, and Jay would be leaving in less than three weeks. He wasn't gonna be there to take care of Erin anymore, and he wanted to make sure she knew that.

He was afraid that once he told her, things were going to change, and not for the better. He knew she'd get distant, and that she'd start to shut him out. He didn't want that, he wanted as much time with her as humanly possible before he'd be leaving for at least 4 years.

He didn't want to tell her they way he did. It was a Tuesday night, she was partying on a Tuesday, and called Jay at 3am to pick her up from some guy's house. He went, of course, but he wasn't happy about it. "Erin, things are going to have to change soon. I'm not gonna be able to keep saving you, you need to do something about this, problem, you have."

Erin rolled her eyes, "I don't have a problem, Jay. My mother has a problem, I'm just… having fun." She said in irritation.

"Damnit Erin, you don't get it, do you? I graduate in 12 days, and after that, you know what's gonna happen? I'm leaving. I have training for the military and I'm not going to be around to help you anymore! You need to take care of yourself!"

Erin looked at him, shocked, tears pricked in her eyes, "Stop the car."

Jay shot her a confused look, "What?"

"Stop the car, Jay! You don't wanna 'take care' of me anymore, fine. Just let me out of here."

"Erin, that's not what I meant!" He reasoned, trying to get through to her stubborn self.

"Let me out of the fucking car Jay Halstead!" She screamed, which finally caused Jay to pull over.

"Erin, please. Don't get out of the car; let's talk." Jay begged.

"I think we've done enough talking, Jay. Have fun in the army." She angrily grabbed her bag from the backseat of Jay's car and started walking in the opposite direction, with no destination in mind.

Jay tried to get a hold of her. He called, he texted, he even asked all of their mutual friends if they'd heard from her, but she seemed to have dropped of the face of the Earth. Come a week after graduation, Jay left, along with the thought of ever seeing Erin Lindsay again. His only wish was that they parted on better terms, and had an actual goodbye.

12 Years Later

Jay walked up the steps to the Intelligence Unit of the 21st district. He made it, he was finally working with the big dogs. Ever since he returned from Afghanistan one of his long term career goals was to be apart of Intelligence. Granted he had to get shot in order to make it, he did get there.

Halfway up the stairs, he was met with his new sergeant, Hank Voight. Jay's heard various rumors about the guy as he worked his way up, but didn't know what to believe anymore.

"Halstead?" Voight asked, extending his hand for a handshake.

"The one and only." He grinned, accepting Voight's hand.

The pair walked up the rest of the stairs together, and upon reaching the top, Voight cleared his throat. "Alright everyone listen up, this is Jay Halstead, our newest member of Intelligence." Jay took a look around, at his new place of work, taking in his new coworkers.

She was late, as usual. She was the only one that could get away with it too, considering her relationship with Voight. She heard from Jules that there was new member joining the team today. A part of her was thankful that she would finally be assigned a partner, but another part saddened at the fact she wouldn't be spending her work days with Hank anymore.

The second she heard his name she raced up the rest of the stairs. It was unbelievable. She only saw the back of him, but right away she knew it was the same Jay Halstead. He was a lot less scrawny than he was in high school. Definitely more built in terms of muscle mass. Without word, she crept up behind him and wrapped her arms around his muscular frame, taking in his scent that was somehow the exact same it was all those years ago.

He was shocked at first, but the second he realized who it was he turned in arms, and lifted her off the ground. "You did what I told you." He said, after releasing her.

Erin shrugged, and glanced towards Voight, "No, just fell into the arms of another man, Jay." She said with a laugh. She hugged him again, tighter this time, as if she was afraid this was dream and at any moment it could be over. "I thought I'd never see you again." She mumbled into his shirt.

The rest of the unit shared looks of confusion, none of them had ever seen Erin show this much emotion with anyone that wasn't Voight. They all looked at Voight, who had no idea what was happening himself. "And if you two are ready to be detectives, we have a case that needs , if you wouldn't mind debriefing. Erin, my office." Voight said in a stern voice.

"What's up with you and Halstead?" Voight asked once Erin was sat in front of him.

"I knew him before I met you, we sort of, ran in the same circles." She struggled to explain what she and Jay had. While their relationship had always been platonic, she always felt there was a flame between them.

"Is he bad news?"

Erin scrunched her face and smiled, "Jay? He was as square as a Rubik's Cube back in the day. He, took care of me, I owe him my life on several occasions." Her voice got lower as her sentence ended.

"He was the 'me' before I came along, huh?"

Erin smiled, "Yeah, you could say that."

As their day was coming to an end, Erin approached Jay, "You wanna go get a drink?" She asked softly. Jay looked at her with a raised eyebrow, and she knew what he was thinking. "It was never the alcohol I had a problem with."

Jay let out a breath he didn't know he was holding and laughed, "Then yeah, let's go, partner."

Erin proceeded to tell him all about life after he'd left. How Voight helped her get her life back on track. All about the rest of high school and becoming who she is today. She explained to him the regret she felt leaving him that night, how she wished she could have reacted differently.

"How come nothing ever happened between us, Jay? I mean, you were always helping me out, with nothing in return. Why'd you do that?" Erin asked when it seemed like they'd talked about everything.

"I guess, I felt that if anything ever happened, I'd be taking advantage of you. Besides, you were only 14, and as badly as I wanted it to, nothing could have prompted me to take advantage of a 14 year old." He avoided eye contact, feeling slightly pervy at the fact that he was almost 18, and attracted to someone so young.

Erin stood from her barstool and leaned into him, "I'm not 14 anymore." She whispered, her hot breath touching his skin. "And you're not taking advantage."

The end! You can use your imaginations to decide what happens next! Nicole, I hope you liked it and it was what you had in mind! I changed a few minor details, but I hope it was still worth your while!