A/N: In this story Charlie didn't come back to Chicago in the first season and he never had a kid with Annie. (Also I don't own any of the characters of Chicago P.D.)

"I think that's the last of it," he heard her voice.

Erin and Jay had just finished the paperwork after arresting Trent's killer and they were about to head home. She had been trying to avoid him all day and he could tell, Voight could tell, everyone could tell. Usually they would finish up at the station and then go home together, but that was before. Neither one of them knew what to do now.

He tried to meet her eyes, "Let me walk you out," he offered.

She just nodded and grabbed her coat. They walked down the stairs and when they reached the bottom they were met by Platt.

"Hey Erin," she started, "there's a man here to see you, kinda hot, smells like cigarettes, said his name was Charlie."

Jay saw her entire body tense but she seemed to recover quickly.

"Where is he?"

"Waiting by the door."

Erin mumbled a quick thanks and walked over to the door, Jay trailing behind.

When they opened the door to the street Jay saw a man, presumably Charlie, push himself from the wall and stomp out a cigarette.

"Erin," the man spoke, "it's been a long time."

"What brings you here Charlie?" Jay could tell that she was trying not to say the wrong thing and offended the man. He could also see that she was uncomfortable and he wasn't sure weather or not she was even aware of his presence anymore.

"I heard you've got something of mine." The statement sounded like it was laced with an unspoken question.

"You heard wrong," Erin deadpanned.

"Are you sure about that?" He asked.

"Yeah," Erin sighed, "so why don't you just head home Charlie, no need to cause trouble over ancient history."

Jay knew that she was trying to keep the conversation civil, what he didn't know was why.

Charlie's eyes seemed to get slightly darker and his voice came out hard, "Chicago is my home, or did you forget?" The man took a step forward and Erin leaned away a bit but kept her feet planted. "And besides," his voice came out lighter this time, like nothing had just happened, "if it's ancient history like you said, there's no need for any trouble. Let's just let the past be the past."

Erin looked down and nodded, "Yeah, okay sure Charlie."

"Good, we're good. You have a good night Erin," he kissed her cheek and she didn't seem to be surprised, "you too officer," he nodded behind her to Jay. Charlie winked at Erin and started walking down the street away from the two.

Erin had seemed to just start to remember her partner was there and looked extremely uncomfortable. Jay was about to ask her what the hell just happened but he was cut off by Charlie's voice calling with his back towards them "I'll see you around girl." He turned the corner and Erin let out a breath, then turned around to Jay.

"What was that all about?" He asked trying to sound casual. He was pretty sure he was failing. Hard.

"Just an old friend," she said vaguely.

"That didn't seem very friendly to me," he pushed.

"I just haven't seen him in a while, I was caught off guard."

He wanted to push the subject further but he could tell that was all the information he was going to get out of her for now.

"Right, well anyways, do you want me to take you home?" He offered, hoping she would take him up on it. He didn't really feel ready to leave her for the night. He knew it was his decision for them to be apart, but he didn't exactly expect it to be this hard.

"That's okay, I think I could use the time to clear my head. Been a long day, you know?" She responded, not meeting his eyes.

He felt disappointed with the answer, but he wasn't going to push it. "Okay, goodnight Erin."

"Night," she gave him a small smile that didn't exactly reach her eyes and started to walk away from the station.