A/N: I have no right to be starting up another fic right now, I know I suck and I should probably focus on the fics I've already started, but this idea floated into my head and won't find its way out. I've thought a lot about this, and I think you guys will really like it. Enjoy!

Halstead was awoken by a sharp knocking on his door at 7am on his first day off in weeks. To say he was angry would be an understatement. He made his way to his front door and opened it with a heavy force, he got even more frustrated when he didn't immediately see a face on the other side of it. After taking a look around, he figured it was probably someone messing with him; until he looked down. There in front of his door, sat a sleeping baby in a car seat, along with a diaper bag. Jay took another look around to see if he could find the child's parents, but had no luck.

As if on cue, the infant began crying, Jay instantly froze. What was he supposed to do; he'd never taken care of a child before and he didn't even know who this kid belonged to, the last thing he needed was to be accused of kidnapping. He figured his best bet was to get the baby to stop crying, so he bent down and picked up the car seat and diaper bag, revealing a manila envelope underneath the bag. He reached down to pick it up and placed it into the car seat next to the screaming baby. Jay walked into his apartment and took the baby out of the seat. "Baby now, envelope later." He said to himself. He could sense that the child was scared and confused, and he tried to be as gentle as possible. He gripped the baby's bottom to check if she was wet, and when he felt the heavy diaper he knew that was probably the reason for her tears. Still carrying the baby, he walked back over to his couch and opened the diaper bag in hope of actually finding some diapers. Upon opening the bag, he found it was filled with all the necessities; bottles, formula, diapers, pacifiers, blankets and several pairs of pants and onesies. He grabbed a diaper and laid the infant down on his couch.

The poor baby was still screaming her head off, and Jay was getting anxious. "Shhh, it's okay. Do you need a diaper change?" He said in his best baby voice, in attempt to sooth her. It took several minutes, but eventually Jay was able to securely fasten a fresh diaper onto the young girl. He picked her back up, and she was beginning to calm down. He took a pacifier from the bag and stuck it into the baby's mouth. He lay her against his shoulder and started to pat her back and bounce her up and down. About twenty minutes later, he could hear her breathing even out and realized she had fallen asleep. He took a sigh of relief, now it was time to see what was in that envelope. Halstead walked towards his bedroom and placed the sleeping infant onto his bed. He surrounded her with pillows to prevent her from falling off the bed and went back to the living room. He found a baby monitor in the bag and decided to set it up, so he'd be able to hear her in case she woke up.

He took a seat on his couch and took the manila envelope from where he left it and flipped it open. Inside, there were a variety of papers. The first thing to catch his eye was a second and smaller envelope with his name written neatly in cursive across the front. He tore open the envelope and began reading.

"Dear Jay,

I'm sure you're pretty confused right now. My name is Anna Hart, and I'm not sure if you even remember me- but about a year ago we fooled around a few times. We met at that bar on Oak Street and really hit off. Anyway, after we broke it off I found out I was pregnant. You're the only possibility as the father, I wasn't sleeping with anyone else during that time. The pregnancy went normally and on July 12th, 2014 Ava Nicole Halstead was born. I tired Jay, I really thought I'd be able to care for her, but I was wrong. I'm only working part time and I can't afford to care for her any longer. I know you're probably thinking how horrible can a person be to abandon her child, but I'm only doing what's best for Ava. We weren't 'together' for that long, but I did get to know you, and I know that you will be an amazing father to our little girl. Everything you need is in the envelope- her birth certificate, shot records, and a Waiver of Interest where I signed away my parental rights. All you need to do is sign them saying you will take on full responsibility and return them to my lawyer at 'Joseph & Johns'. Good luck Jay, and congratulations.

Love,

Anna"

"Oh my God," Jay said to himself after reading the letter. He went through the rest of the paperwork in the file and found the Waiver of Interest Anna was talking about, and sure enough she had surrendered her parental rights, and Ava was all his. He found Ava's birth certificate with his name listed as the father next. Now was the time to freak out. He didn't know why, but his first thought that came to mind was to call Erin, she'd know what to do.

"Hello?" Erin called groggily through her cell phone. It was barely after 8:30am, and she'd had a late night with her boyfriend, firefighter Kelly Severide.

"Erin! I'm so glad you answered." Jay said frantically, although smiling at the sound of her extra raspy morning voice.

"Halstead?" Jay could sense the confusion and annoyance in Erin's tone, "Why are you calling me before 10am on our one day off?" She moved Kelly's arm from her waist and sat up in bed, pulling the sheet with her. Even with her annoyed manner, she knew Jay wouldn't have called her if it wasn't something serious; she knew how they savored their days off and both enjoyed sleeping in late.

"I know it's early, but I need you to come over. I don't know what to do." He was scared, Erin could tell and she was already getting out of bed. She didn't know what was going on, but she knew it was bad. Jay and Erin had a promise to always have each other's backs- at work or not- today was no different.

"Don't worry, I'll be right there." She said with a rush and hung up the phone without waiting for a response.

Erin sat on the edge of the bed to put on her shoes. She suddenly felt lips on her neck and began to smile, "Come back to bed," she heard Kelly say in a clearly seductive voice, while pressing kisses up her neck behind her.

Erin let out a slight laugh, "I can't, I have to go help Jay." She stated matter-of-factly.

"He's a grown man, I'm sure he can take care of himself." Kelly said, grinning before returning his lips to her neck.

"Kelly, he'd be here in a second if I needed anything; I'm not going to turn my back on him now. Besides, he wouldn't have called me if wasn't something big. I have to go." She got up from the bed and turned around in order to give Kelly a quick peck on the lips. "I'll be back later, lock up when you leave." And with that she was gone. Kelly let out a huff and flopped back onto the bed.

Erin didn't bother to knock when she arrived at Jay apartment. She unlocked the door with the key Jay had given her a few months back. "Jay?" She called out when she walked in. She noticed the car seat and diaper bag on the floor near his couch and continued searching the apartment for him. "Jay?" She called again, a little bit louder this time.

Seconds later, Jay emerged from his bedroom carrying a baby bottle. "Shh, I just got her back to sleep."

Erin looked at him, confused, "You just got who back to sleep?" She looked at Jay in the eye before continuing, more sternly she asked, "Jay, what the hell is going on?"

Jay walked over to the coffee table and picked up the letter. He handed it to Erin and stroked the back of his neck. He gave Erin some time to read it and awaited her reaction. After reading the letter Erin looked up at Jay, she didn't know what to say. "What are you going to do?" Erin asked after several moments of silence between the two.

Jay shook his head, "I don't know, Erin."