This is my first time writing anything but Harry Potter, but I love this show, and this couple, so I thought I would give it a try! This is one of those AU stories. I tried to keep the characters as close to the show as possible but I had to change some things, but that is okay because that is what Fanfiction is for! I hope you enjoy!

Disclaimer: I do not own anything except the storyline!

It had been a long day at work and the Intelligence Unit of the Chicago Police Department was having drinks at Molly's.

"Er, you want another beer?" Jay Halstead asked his partner Erin Lindsay.

"Sure."

Jay started to pull out his wallet and as he opened it something fell to the floor. Erin bent down and picked it up.

"Hey, Jay," she said as he stated to walk off. "This fell out of your wallet. Who is she?"

Jay grabbed the picture and his demeanor changed instantly, "She is no one." And without another work or look at his partner, he walked off.

Erin was confused. She turned back towards their table and saw that Jay's brother Will had sat down.

"Hey."

"Lindsay." He said will a nod. "Where did my brother run off to?"

"Uh, I don't know." She said. "Hey, Will. A picture fell out of Jay's wallet."

"You detectives always have to find answers don't you." Will said with a smile and took a drink of his beer.

Erin rolled her eyes, "Forget it."

"What was the picture of?"

"It was a little girl, maybe around age six. Light brown hair a little past shoulder length and blue eyes."

Will looked down at his hands, "Oh yeah."

"Do you know who she is?"

"Yeah. I do know who she is."

"Are you going to tell me?"

"Maybe if you would have waited just a little longer, I would have told you when I got back." Jay said as he put a beer down in front of Erin.

"Who is she, Jay?"

"Well, her name is Lydia."

"Okay. How do you know her?"

"I have known her for quite some time."

"Stop beating around the bush, Jay."

"She is our sister." Will said as he drank the rest of his beer and set the bottle down on the table.

Erin was stunned, "You have a sister? Why didn't you tell me, Jay?"

"She was kidnapped while I was deployed and Will wasn't around. She was just taken right off the street walking home from school. The picture I have was her most recent school picture before she was taken. She was 8 at the time. We haven't seen her since." Jay said and then proceeded to walk toward the bar and get another beer.

Erin looked at Will who had been silent. He was staring at his hands and he looked extremely upset.

He took a deep breath and looked up at Erin, "I had just started a residency in New York when she disappeared. I was the first person that they called since they couldn't get ahold of Jay. I was on the next flight out here and when I got here, there was nothing. They had no leads and they told me that they would keep looking, but that was the best I got. So after about a month, there was a couple of possible leads but they couldn't find anything else. I couldn't stay in Chicago anymore knowing that she was missing. I went back to New York and that's where I stayed until I got fired and came here."

Erin had no words, so she just put her hand on Will's shoulder.

"The worst part is that Jay was deployed so he didn't find out for a while. He blames himself for the whole thing. He was 19 and he left her here with a family friend. He thinks that if he would have stayed here, it wouldn't have happened."

"That's crazy." She looked over at the bar and found Jay. He had just finished another beer and was asking Herrmann for another one.

"Well try telling him that. He blames himself and no matter what I do, I can't convince him otherwise."

"Hey, Will. What precinct handled the investigation?"

"I don't know but it wasn't the one you two work at."

"I will be right back. Don't let him drink to much more."

"Okay."

Erin walked out of Molly's and took out her phone and dialed a number.

"Hey, it's Lindsay. Could you do me a favor? Great. I need you to look up a case from about 10 years ago for me and send everything you find up to Intelligence. Thank you." She hung up and walked back in the building and headed back to Will.

She got back to the table to find Will and Jay both sitting there.

"Hey. How are you holding up?" she asked Jay.

He scoffed, "Just great, Er."

She rolled her eyes and sat next to him. She placed her hand on top of his and said, "I know you are hurting, both of you, but I had an idea. I called a friend and he is going to dig up every bit of information on the case and send it over to Intelligence. It should be there tomorrow and I am sure the Voight will let us look into it."

"Do you really think he will?" Will asked her.

"Yeah. He is a good cop and he cares about all of us. Even if he doesn't say it in so many words."

"Thanks Lindsay. Anything you can do would be a real help." Will replied.

She looked at Jay. He was staring at her, "What?"

He leaned forward and kissed her forehead and pulled her into his arms, "Thank you, Er. Just, thank you."

So what did you think? Feel free to leave a review!