Kate submitted her blood and tissue samples as directed, hoping for the best as she prepared for what would seem like an endless wait. It would take two full weeks to determine if she was a viable donor for her daughter.

In the mean time, Mia was finally allowed to go home. However, it was with no small amount of help. Castle hired a physical therapist to stay at the loft, where Mia (and Kate) would be living for the foreseeable future.

"The loft has extra rooms, easy access on the ground level and plenty of room for Mia to rest and recuperate. Not to mention it is completely secure."He reasoned with Kate.

Beckett had to agree, they'd been there previously and Mia's things were already there. It didn't make much sense to upset whatever stability they could provide the teen.

Although they'd been close in the hospital, once back at the loft Castle and Beckett soon returned to a routine of sleeping in separate beds. There was an unspoken agreement to take things slow and while they both agreed that a conversation about where they were headed was needed, now simply wasn't the time. Castle also couldn't help but notice that Kate began to pull away since learning about Mia's latest health complication. He figured she needed space to process, but hoped she would open up to him soon.

For the most part all of their focus was given to Mia, to helping the girl recover as quickly as possible. Kate sometimes watched helplessly as the teen struggled through her physical therapy sessions, her broken bones healing but her muscles atrophied and strength gone. It was painful for Mia to experience and it was difficult for Kate to watch. If she could she would have gladly volunteered to take her daughter's place.


Lanie worked in tandem with the hospital as they collected samples from willing participants. She volunteered her help to speed the process along, grateful that her official affiliation with the hospital made such collaboration possible.

Even so, the cross matching could not be rushed. Only time would tell if Mia's blood and tissue samples would react well to those of her mother. Lanie was pleased to learn that Kate, Alexis and Ryan were all matches in Mia's A+ blood type. However, she, Martha and Esposito were not. Castle was also not a match, but his O- status kept him in the running as a universal donor.

Starting with the three matches, along with the remote chance of Castle's blood, Lanie explored and tested four separate sets of tests, each matched to a sample from Mia. It was a long and frustrating two weeks and she observed daily how the cells interacted. It became clear to her fairly early that Mia's cells weren't taking kindly to most of the samples. She felt a sense of foreboding as Kate's blood seemed to be no exception to this trend.

What interested her was that one set seemed to work; Mia's cells seemed to act as if they not only tolerated but recognized the cells. It was an early indicator of a potential match- so far, so good. Usually this was seen with blood relatives only. Curiosity got the best of Lanie and with blood samples in hand; she began to conduct other tests as well.

The medical examiner isolated white blood cells from both samples, adding a chemical here and an enzyme there, Lanie soon found what she was looking for. One final test, she thought to herself. Although she knew she didn't have medical consent to conduct such tests, Lanie took it on faith that her friends would want to know. Everything found in the un-ordered tests would be destroyed and stay on the down low if need be. When the results were finally apparent, she swallowed her surprise, processed the information as best as possible, and made her way to the loft. It was time to deliver the news.


It was a Tuesday afternoon and Mia was going through the motions of her physical therapy, gradually increasing range of motion in her arm and leg, building strength in her lower back and hips. Kate read a book quietly, listening to the rhythmic typing of Castle at work.

Even after all they'd been through, she still found his steady keystrokes to be soothing. His typing added a sense of normalcy, of domesticity to their lives. A smile pulled at her lips as she thought once again of Heat and Rook, pondered on the unlikely scenarios Castle was placing them in.

When the buzzer sounded she jumped from her place on the couch, no question as to who it was. Afterall, it had been two weeks and she'd been waiting all day. Placing her book on the counter, she made her way to the door to open it, invite Lanie inside and to hear the news they'd been waiting for.

"Well?" She blurted as soon as Lanie was seated at the dining room table. Castle had also moved to join them. Mia was busy at work with her therapist in the next room and they did not want to expose her to potentially bad news until they'd had time to process it. The tension between the three adults was unbearable as Lanie once again looked over the well-memorized test results. Both Castle and Beckett found themselves on edge and hoping for a miracle.

Lanie looked to the both of them, shaking her head. "I'm sorry sweetie, but you're not a match." She broke the news softly. Kate swallowed back tears, her hands gripping the table to support her as she processed the news. The one thing I could have done to protect and save her, the ONE thing-and I failed. The tears came quickly as she swallowed back the bitterness and devastation.

"What about me? I'm a universal donor." Castle offered hopefully. He wished against all odds that somehow he could offer this piece of himself.

Lanie shook her head again. "You're not a match either." She spoke, allowing him to deflate as well. She needed to be careful with her news, calculating the timing if they were to understand it and take it well.

Kate felt the floor fall out from under her. Despite the doctor telling her that a parent had less than a 25% chance of being a match, she'd hoped that she could offer this one thing. She was desperate to somehow make up for lost time, to protect her daughter. She felt like a failure all over again. Castle was silent, simply moving from the table and retreating to his study. He didn't wait around, too heartbroken for the remainder of Lanie's news.

His rapid departure surprised Kate, as Castle was usually right beside her-even during times of devastation and heartbreak. It drove home for her just how badly he wanted this as well, how helpless he felt to make things better for Mia.

Lanie allowed him to go in silence. It was better that Kate take the next piece of news alone.

Beckett held her head in her hands, letting out the breath she'd been holding. She began the process preparing herself to break the news to Mia. However, Lanie broke through her thoughts, being very careful about her wording.

"Kate, there's more." She began, "We did find Mia a match." The detective's head shot straight up.

"What the hell, Lanie! You could have opened with that!" She blurted, relief flooding her system. She wanted to strangle and hug her best friend at the same time.

"Kate, listen to me. Alexis was a match, she is a great donor candidate." She allowed Kate to absorb the good news before continuing, "In fact, she was a damned near perfect match." She stated.

"That's great!" Beckett blurted.

She waited for Lanie to smile, to share in her relief and joy, but it didn't happen. Before long she started to truly think about it. She hadn't anticipated that someone else would be a match, let alone Castle's daughter.

What if Alexis refuses? No, she'd never do that. Kate countered to herself. How could I ask for such a thing? What would Rick say about his daughter losing a kidney? Insecurities flooded her mind nearly as quickly as the relief over hearing they'd found a match.

"Does Rick know she got tested?" Kate questioned, surprised that she didn't know the answer to the question herself. She'd been so absorbed by the possibility, by the perceived probability that she would be a match that she hadn't considered who else was tested.

Lanie nodded, "He does, and that's a discussion you can all have later." She asserted, needing to continue the conversation.

"There is one last thing Kate." The medical examiner added, no small amount of hesitancy in her voice.

"I'm not really sure how to say this, but…"

"Just say it, Lanie. Whatever it is, I can handle it. Is there some reason why Alexis wouldn't be able to donate? Were her blood levels abnormal? Was her kidney functioning ok?"

Again, Kate gravitated to the worst possibilities. All ended with Mia losing her best shot at a healthy life, or Alexis' health compromised, or Rick eventually hating her for harming his daughter or for suggesting that Alexis lose an organ. The prospect that Alexis herself could be sick was unbearable.

Lanie could see Kate's thoughts spiraling out of control like a runaway train,

"No, Kate- just listen to me." Lanie became assertive, taking Kate's hand into her own. "Alexis was a near perfect match, more so than one would expect from a stranger." Kate nodded, unsure of where the conversation was going.

"Out of sheer curiosity I pressed a little more, compared their samples, and I found something interesting, Kate." She refused to break eye contact as she continued, "Mia and Alexis are a partial match on a genetic level." Now Kate was lost.

"I don't understand. What does that even mean?" She stated.

"They're not a full match, but they do appear to share half of their genetic code. That's close enough to suggest that they share a blood relative, and not just any relative."

"I'm sorry?" Kate questioned, clearly not getting the point Lanie was trying to make. Are you trying to tell me that Mia's not my daughter? She thought for a moment.

"Kate, I'm telling you that Mia and Alexis share a parent, they're siblings-and considering that you are not Alexis' mother, I'm pretty sure that the parent they share is their father."

Color drained from her face as she finally absorbed the news. Not possible, echoed through her mind again and again.

"I ran a DNA test to confirm…" Lanie offered.

"So, you're telling me…" She couldn't get the words out.

"I'm telling you that Richard Castle is Mia's biological father."


AN: Surely you saw that coming, but a little less direct perhaps? :)