Let me know what you think! There's going to be a whooooole lot more to unpack.

"Hey," Jay swallowed, taking a few steps closer to his former partner. Her hair was darker and shorter than it had been in Chicago, and her cheeks were slightly more tan. She'd been getting better sun in New York, apparently. Erin wore black jeans with a dressy grey top, complete with a forest green blazer. She looked professional, put together and incredible save for the exhaustion in her eyes. "Good to see you, Er."

Erin's lips twitched upwards at the familiar nickname. Jay looked good. He always looked chiseled, rugged and sexy, but there was something about him that was…softer. She couldn't place it, but when she met his eyes she felt her knees weaken. He really was handsome. "It's really good to see you, Jay." She paused, "I-I was on an assignment, I didn't get Hank's messages until late last night, but I drove here as fast as I could when I found out."

Jay managed a nod, remembering why his ex was back in town. She had a little sister. The same little sister who'd been living with Jay for over a week, and who he was fiercely protective of. "He filled you in?"

"Just that you guys found a kid whose DNA is a match for Bunny," she replied, nervousness now evident in her voice, "I-I haven't heard more than that. He's on his way back from a meeting downtown, you're the first person I've seen."

He nodded again and shifted his stance. "She looks just like you," he offered, "And um, she's actually a lot like you too." As Jay continued to regard the woman in front of him, he could see that her eyes were wet with tears, like she'd been crying for some time.

"I just um, can't believe it," she whispered, "That she exists. That I didn't know." Erin cleared her throat, "I uh, didn't think I'd ever be back in Chicago."

Jay was silent. He didn't think she'd be back either. Truthfully, he didn't really know why she left. He knew that he'd fucked up, but he never thought it would drive her across the country. "I tried calling," he managed, "When you first left but I um, gave up."

"I couldn't," she shook her head, "It's complicated."

He simply nodded again. "We don't have to talk about it. You're here for Piper."

"Piper?" Erin sucked in a breath, "That-that's her name?"

"Yeah," Jay offered a small smile, "She's nine. Pretty smart, real observant. Hates pickles."

Tears filled Erin's eyes again, "Does she um, does she know about me?"

"We were waiting to tell her til we knew for sure. She's a DNA match for your mom but uh, DCFS needs to make sure that she's a match for you too, before anything happens. Piper um, she doesn't know about Bunny either. And Bunny doesn't know, for that matter."

Erin shook her head, "I gave her so many chances. I, I practically tossed my career for her and-"

"Did you just say that you tossed your career for Bunny?" Jay raised his eyebrows in surprise, "That's why you left?"

"It's complicated," Erin repeated, wiping her eye with her index finger, "Where is Piper?"

"We didn't want her to go back into the system, or to Bunny," Jay said slowly, realizing that Erin had no idea her sister was staying with him, "The guys who had her are still out there, so she's been in protective custody, with me actually."

"With you?" Erin's eyes softened further and she exhaled. "Oh, thank god. I thought they put her back in the system, that she was alone but…" she trailed off. "Thank you."

"She's really great," Jay told her, "Kid's been through a lot, and um, I was the one who found her, so she's pretty trusting of me, which is good. Definitely nervous around new people but she's real brave."

"I can't believe you found her," Erin mused, "I'm just so glad it was you, you know?"

He nodded again, "Me too. She's with DCFS now, I guess part of this whole process is that they need to interview her alone. I'm supposed to pick her up in a bit, and I'll bring her back here so you guys can meet."

Erin nodded. "I got a temporary transfer to Chicago. A desk job, for the next few weeks. Hank said that there's probably going to be a series of court hearings, making sure that Bunny's parental rights are dissolved, and that I'm suited to take care of her."

"You are," he assured her, "And that's good. Piper's bounced around a lot and it might take a bit of time for her to warm up. Are you staying with Voight?"

"I got a short term lease on a furnished place," she said, "Around the corner from Stanton Park."

"No way. My place is across the street from there." Jay was genuinely shocked at the coincidence. "Guess we'll be neighbors for a bit."

"Hey, kid," Hank greeted just as Erin was about to reply, "Good to see you."

"Hi Hank." Erin held tightly to her father figure, "Feels good to be home."

Hank cleared his throat, "You two get caught up?" Both Erin and Jay nodded wordlessly. "Good. My contact at DCFS says that Bunny needs to be notified about Piper, and that we need a confirmed DNA test to make sure that Piper can stay with you." He gestured to Erin, "They'll probably let Bunny know tomorrow since it's getting late today but-"

"I want to tell her," Erin interrupted, "I need to hear it from her, and make sure she doesn't try anything."

Jay and Hank raised their eyebrows in surprise. "You sure?" Hank asked, "DCFS makes these calls all the time-"

"I need to be the one to tell her," she insisted, "I um, she just has to hear it from me, and I want to give her a piece of my mind." Erin swallowed, "She's probably at her bar anyway."

"Well, Jay has to pick up Piper. Halstead, you want to bring her by my place tonight for dinner to meet Erin?"

Jay nodded wordlessly, the reality of Piper leaving setting in. "Yeah, uh, I promised I'd pick her up. And um, Er, if it's alright with you, I can give her a heads up? Just so she's not walking in blind? It's just that she trusts me and-"

"That's good," Erin assured him, "I'm glad she trusts you. I need to go talk to Bunny but I'll see you guys later this evening?"

Jay sat in the Sierra outside DCFS, building up the courage to face Piper again. He was still early, but his heart was racing. Erin was back in town. Piper was going to live with her. He needed to tell her. His heart ached at the thought of Erin leaving again, this time taking his new little friend with her. Seeing his partner again simultaneously filled him up and emptied him.

He was on autopilot as he headed for the DCFS office and sat outside on the hallway bench, fully aware that he wasn't allowed in. He wasn't family, he wasn't anything. He was a stopgap, and while he was happy to play that part for a child in need, every fiber of his being was coming undone at the thought of saying goodbye. Jay exhaled, trying to ground himself. Erin was going to be in town for several weeks, and Piper was still in protective custody. They had more time together, just not that much.

"Detective Halstead?" Jenna O'Donnell pushed open the office door and snapped Jay out of his reverie. "She's all set. You can come see her now."

"Great. How'd she do?" He stood and followed the social worker back toward the office.

"As well as can be expected," Jenna said in an exhale, "She's been through a lot for just being nine. And I know I say that a lot in this job, but every case is just…" she trailed off. "Actually, before you see her. I spoke with Sergeant Voight, and the woman believed to be Piper's sister. Now, I understand Piper doesn't know about her sister, or that her mother is known to the CPD."

"Trying to keep her as far away from Bunny Fletcher as possible," Jay said dryly, "Piper doesn't need that."

"Yes, and what she needs is stability. And if it's alright with you, I am going to recommend to the judge that Piper stay with you, at least until the court hearing in two days. I spoke with your Sergeant who also confirmed that Piper will continue to be in protective custody until the Marsh couple is apprehended, so depending on how court goes, it may be a few days longer. I'll inform Ms. Lindsay as well, but wanted to check with you first. I believe it's in Piper's best interest."

Jay nodded and exhaled. Piper wasn't leaving just yet. "That sounds good. Her whole world is going to be turned upside down, again."

"The stability you've brought even in the last week has been huge for her," Jenna informed him, "Piper spoke about the routines you set up, the way you listen to her and wait for her to come to you – everything you've done has been right. And she's incredibly lucky to have you."

"Thank you," Jay managed, "I feel lucky to know her." He swallowed, "I was going to tell her about Erin today. Introduce them?"

"That's fine. Just as long as Piper goes home with you." Jenna smiled as Jay nodded in agreement. "Hi Piper, look who's back."

Piper looked up from her seat at the table, eyes immediately finding Jay's. "Jay!" she exclaimed gratefully, abandoning her seat and rushing to throw her thin arms around him. He knelt and held her closely against his chest.

"Told you I'd be back, Pipes," he said, stroking the back of her head with his hand, "You okay?"

"Better now that you came back," she mumbled, still holding tightly to the detective, "I knew you would, but I still worried."

"I get that," he murmured, "I do. But you know I keep my promises. How do you feel about a smoothie, hm?"

"Yes please," she pulled back and gave a smile, melting Jay's heart.

"How's the smoothie, kiddo?" Jay asked after swallowing a gulp of his pineapple berry blast. Piper had opted for a strawberry banana smoothie, which was coincidentally Erin's favorite.

"Cold," she shivered slightly but then offered a bright smile, "But really good."

"Did you have a good conversation with Ms. O'Donnell?" he asked, trying to be as casual as he could.

She shrugged in response. "She was one of the nicer social workers I ever met. Asked me about how I was doing instead of just making me sit there, so that was good."

Jay nodded weakly, building up the courage to broach the topic of Erin and Bunny. "So uh, Pipes, while you were talking to Ms. O'Donnell, I got some news." He cleared his throat as Piper glanced up at him nervously. "And it's good news."

Immediately, Piper's demeanor shifted. "You found someone to pawn me off to?" Piper said dryly, "And I'm leaving?"

He tried to pretend that the little girl's words didn't sting, but they did. "We found your birth mother," he said, clearing his throat again, "There was a DNA match for you in the system."

Piper kept her lips together as Jay continued, "She um, isn't the best fit to take care of you though."

"I mean, she abandoned me," Piper snapped, "Never tried to get me back. Left me in the system for my whole life because she didn't want to sign away her parental rights."

Jay raised his eyebrows at Piper's statement. "I've been listening to the social workers talk for years," she informed him, "She's the reason I couldn't get adopted or whatever. Not that anyone would want to adopt me."

"Piper," Jay shook his head, "You are an incredible kid. And whatever your birth mother did, or didn't do, that is not your fault." He paused, "When we found your birth mother, we also realized that she had another child a while ago. She's your sister, and her name is Erin."

Piper's gaze remained cold. "She in foster care too?"

Jay shook his head again, "No, she's not. She's actually an adult, about my age. Erin works for the FBI, and she's really looking forward to meeting you."

"How come she didn't know about me before then? If she's a grown up." Piper narrowed her eyes, "Wouldn't the woman who gave birth to both of us tell her?"

"I-I don't really know, kiddo," he said honestly, "But I can tell you that I actually know Erin. Before Hailey, Erin was my partner in Intelligence. She's really close with Sergeant Voight, and he invited us all over to his house for dinner tonight."

"You know her?" Piper jumped up from her chair, "And you didn't tell me?" Angry tears filled the little girl's eyes, "Is-is that why you let me stay with you?"

"No, no," Jay refuted, "We're still waiting on Erin's DNA to come back, but since you were a match for her mom, I wanted to tell you. I didn't know that Erin could be your sister."

"And where is this mom of mine then?" Piper sniffed, doing her best to keep the tears at bay, "The woman who's DNA is a match for me?"

"She um, well, I don't really know," Jay grimaced, knowing that was the answer Piper least wanted to hear, "She wasn't really there for Erin when she was growing up either."

"At least she knew about her!" Piper exploded, hot tears now streaming down her face, "I just got passed around Chicago for my whole life, alone."

"I know you're angry kiddo," Jay tried, "And I'm not going to tell you that this isn't hard. But Erin is really great, and I know she really wants to meet you. And she wants to be with you, and know you and make sure that you have a stable home."

"She-she wants me?" The little girl hiccuped, shattering Jay's heart yet again.

He nodded fervently, "She does, Pipes. She wants to meet you, and get to know you. And we're going to take it slow, okay? So tonight, you'll just meet her, say hello, have dinner, but you can still come home with me. And then once things are settled, we can talk about next steps. But regardless, I'm going to be there for you. For whatever you need."

Piper regarded him through tear-filled eyes. "S-so you're not just going to leave me with her?"

"Not a chance," Jay shook his head, "You're my top priority, kiddo. Keeping you safe is my job, and that means that until you feel good and everyone signs off, I'll be right with you."

Her face crumbled at Jay's kind words. "I'm sorry," she wept, covering her face with her sticky hands, "I-I didn't mean to yell, I don't want you to leave and-and I don't want you to hate me."

"Oh, Pipes," Jay sank to his knees on the smoothie shop floor and allowed her to fall into his embrace, "I could never hate you. I know this is so hard for you. And no matter what, I'm not leaving."

"You'll stay with me? To meet my sister?" Piper asked, her small voice still muffled by Jay's shirt.

"Absolutely," he replied, "Sergeant Voight's cooking dinner, and he's a really good cook. Much better than me."

"You're a good cook too," she murmured, sagging heavily against the detective, "Really good." She paused, "You're sure I can still stay with you?"

"Mm-hm." Jay stroked her hair back, "Ms. O'Donnell said that until a judge signs off on Erin, you can stay with me."

"Twenty-two years!" Erin exclaimed, slamming the front door to Bunny's bar as loudly as she possibly could. The two patrons who were still drinking from the night before lazily looked over at the woman standing in the doorway positively seething.

"Erin! What are you doing back in Chicago?" Bunny offered a smile that quickly faded when she saw Erin's face, "What happened?"

"You happened," Erin spat, "You had twenty-two years to get your shit together from the time you had me, then Teddy and then another kid." She glowered at her mother as realization dawned on Bunny. "When exactly were you planning on telling me that you had another child that you abandoned?"

"I don't know what you're talking about," Bunny shot back and returned to wiping down the sticky bar, "I haven't seen or heard from you in over a year, and now you're suddenly back with some twisted…conspiracy theory! Did Hank Voight put you up to this?"

Erin took a deep a breath as she could in an attempt to compose herself. "I was on assignment. I got back to my apartment to several missed calls from Hank, informing me that Chicago police picked a nine year old child who is a match for your fucking DNA."

Bunny swallowed, "That is simply not possible, Erin. You would have known if I were pregnant."

"You had me when you were fifteen!" Erin shouted, "And then for eight years of my life, I didn't hear from you. So yeah, I would have known you were pregnant if you were around, but you weren't."

"That was Hank Voight's choice," Bunny shook her head, "I wanted to see you, but he wouldn't let me."

"Because you were on drugs," she growled, "From the time I was two years old. And now it's thirty years later and you have managed to fuck up and abandon three different children."

"That is not fair," Bunny protested, "How do you even know this child the police found is mine, huh?"

"DNA doesn't lie." Erin narrowed her eyes, "Are you – are you high right now?" She put her hand on her forehead in aspiration when Bunny didn't deny it, "Jesus Christ, I thought you were supposed to be sober. That was the whole reason I threw my career down the tubes so you could live a healthy normal life."

"Why didn't I receive a call, then? If this child is in fact mine, shouldn't her mother have received a courtesy call?"

"Maybe you did get a call and you just don't remember," Erin bit back, "There's about twelve years of my childhood I know for sure you don't recall."

"Just as well," Bunny snarled, "Always did remember you being a little bitch."

Erin set her jaw, "Don't contact me, ever again. And do your other daughter a favor and stay out of her life."

"I can't believe her." Erin paced back and forth in Voight's kitchen while he prepared dinner before Piper and Jay were due to arrive, "Of all the fucked up twisted shit that Bunny was in to, abandoning a child? I mean, she was on drugs for most of my childhood. Left me and Teddy alone for days on end but I never thought she'd just leave her child in the system. And all those times she supposedly got clean and was trying to make amends, she never tried to get her back? I mean what the fuck?"

"I know, kiddo," Hank shook his head, "She never ceases to amaze me with how low she'll go."

"It sucked growing up with Bunny," she managed, sinking into the kitchen chair, "She was always high, or with some guy, or leaving me and Teddy to fend for ourselves but at least I knew where I came from." Erin swallowed the lump in her throat, "This poor little girl has been alone for nine years, with nobody looking out for her. And the worst part is, I could have been there."

"This isn't your fault," he said pointedly, "You didn't know about her. I didn't know. Hell, with the amount of drugs she was doing, I'm sure half the time Bunny didn't know. But this is on her. And you drove through the night to come meet your sister, and you'll be there for her in ways your mother wasn't for either of you."

Erin gave a watery nod. "Jay's been lookin' out for her?"

"And doing a great job," Hank said gruffly, "Piper's skittish, and rightfully so. Somehow Halstead's gotten her to trust him, and that's going to be really important for you in getting to know her."

"I guess it's good she'll be staying with him til we see the judge," Erin exhaled, "I get that they need to make sure I'm suitable, inform Bunny and whatever. I'm just so glad she's not in the system."

Hank nodded, "You can thank Halstead for that as well. He basically refused to let her out of his sight."

Jay turned around in the back seat to face Piper after parking outside Voight's house. "You ready, Pipes?"

"You're staying, right?" she asked, needing another confirmation that Jay in fact would not be leaving.

"Yep. The plan is for us to have dinner with Erin and Voight, and then we'll head back to my place to watch the end of the game. I'll be with you the whole time, and you're coming back with me." Jay gave a smile and unbuckled before helping Piper out of the backseat.

"What if she hates me?" Piper asked, stopping in front of the Sierra while Jay walked toward Voight's front door, "What if she meets me, and hates me?"

"That's not going to happen," Jay promised, turning around to meet the child's anxious gaze, "You are an incredible kid. Erin's going to love you, and I have a feeling that you're going to love her as well."

Piper gave a small smile. "You know, I think you're the first grown up who ever told me I was incredible."

Jay could have cried at that, but instead he sank down so he could look directly into her eyes. "Well, I may be the first, but I certainly will not be the last. I'm so proud of you, kiddo. For being so brave."

Piper wrapped her arms around Jay's neck and held tightly, "I'm so glad you found me," she whispered as he hugged her close, doing everything in his power to keep his eyes dry.

"Me too," he whispered back. He placed a gentle kiss on her forehead before extending his hand, which Piper gripped tightly. "Let's go meet your sister."

"You wanna get it?" Hank asked, roast potatoes in his hands as he closed the oven with his foot, "Got my hands full." When Jay had knocked on the door, Erin had frozen.

She nodded, her heart in her throat. On the other side of the door was her sister. Her sister, and her former partner. She took as deep a breath as she could before pulling open the front door.

There, on the front stoop of the house she'd grown up in, was Jay Halstead, accompanied by a tiny little girl who was most likely her sister.

"Hi," she swallowed, taking in the splitting image of her younger self, practically attached to her ex-partner and ex-boyfriend's hip, "My name is Erin and um, I'm your sister."

Next up - Piper and Erin meet. Thank you again for everyone leaving reviews! They've kept me inspired :)