Richard Castle knew Kate Beckett had missed him. She may not have been as demonstrative as Alexis, who had run up to him in baggage claim at JFK and thrown herself into his arms (though he certainly wouldn't have minded if she had). She may not have even given him the back-slapping hug he got from Ryan and Esposito on his return to the precinct. But Rick was a details man. And in this case the details were all clues in the case that pointed to one thing; the detective was glad to have him back.

Exhibit A: She let him pay when he had taken her and Alexis out for dinner to celebrate his return last night. (And yeah, ok some might think that that only meant she missed his Visa Gold Card, but Beckett was the kind of girl who made her own way. And not putting up a fuss or trying to pay because she knew it would make him happy? That was a thing.)

Exhibit B: She hadn't objected when he sat in between her and Alexis on the couch when they got back to the loft after dinner last night. In fact after a few minutes she'd leant into his side, and let him put his arm over her shoulders.

Exhibit C: She had made him coffee this morning.

And the final, pièce de résistance, was right now. She was letting him drive her Crown Vic on their way home to get ready for the book launch tonight. Sure it was probably because Madison had called just as they were leaving the precinct. But six months ago she would have told Maddie she would call her back and then driven the car. But today she had just wordlessly thrown him the keys and gone around to the passenger side.

That was a lot of evidence considering they had only been back in the same time zone for twenty hours.

Rick knew it was all in the details. And the details said Kate Beckett wanted Richard Castle around.

"Hey Castle," Beckett interrupted his musing from the passenger seat beside him. "Didn't Maddie look hot in that red dress she wore when we went out to dinner before the summer?"

"There is no correct answer to that question, Beckett." If he said no, Madison could totally overhear and hate him (and he'd be lying). But he wasn't about to tell another woman she looked hot right in front of his…uh…work partner? Live-in muse? They really needed better labels. Preferably girlfriend. Or lover. Or – perhaps most honestly – love of his life.

"Castle," said Beckett in frustration.

"What? A man has a right against self-incrimination. I take the fifth."

"Man up, Castle. If I was a guy I would have been all over that." Castle could faintly hear Madison's tinny laughter from the speaker.

Oh, God. Kate Beckett, all over that. Only in the fantasies that instantly flooded his mind, she was definitely not a guy.

Kate Beckett and Madison Keller.

And skin.

Oh.

When he came back to reality a few moments later it was to Beckett calling his name.

"Castle? Castle?" called Kate, her hand covering the cell. She moved to speak into the phone again. "I think I broke him," she told Madison. "Wear it. When have I ever led you astray?"

Silence for a moment as Madison obviously provided an example. "That was junior year!"

He tuned back in to Beckett's half of the conversation, his radar for personal details and potential blackmail piping up. "It was not my fault the teacher intercepted the note. It was improperly folded! If I hadn't spent so long trying to flatten it out so I could read it, he wouldn't have come past."

Silence for a moment, then: "There is so a statute of limitations on improper note passing!"

"Pfft, public humiliations. You want to talk about high school humiliation? Let's talk about Valentine's Day senior year, huh?"

"Yeah, I didn't think so."

"Look, just wear the red dress. Tom won't be able to keep his eyes, or his hands, off you. You can thank me later. Oh!" Beckett turned to Rick suddenly. "Um, Castle, I may have told Maddie she could bring Demming. That's ok, right?"

She was turning back to the phone before he could answer. "Yeah, well I'm asking him now, alright?" she told Madison. Beckett looked back at him expectantly.

"It's fine," Rick said, amused. "I'll let Gina know to put him on the list. In fact, if you want to add anyone you can call her anytime. She knows I do whatever you say." He ignored Beckett's indigent snort at this and keep speaking before she could interject. "Tell Madison I'm glad they're coming."

"Did you hear that? See, told you it would be fine." Beckett listened for a moment. "Maddie says hi. And thanks."

Beckett listened for a moment. "It does not mean any-" Beckett broke off and looked at him furtively. "I'm not discussing this now."

Madison obviously asked a question, because Beckett looked at him surreptitiously again and angled her body away from him and toward the car window. "You'll see tonight," he heard her say quietly. Castle figured she must have been asking about Beckett's dress, since the detective had been unusually secretive on the subject. Rick wasn't sure if that was because she was nervous about the dress or trying to knock him out with how good she looked. He figured it was most likely the first reason, but either way he was sure to be floored.

Floored was an understatement.

She came down with the stairs with Alexis, their arms around each other, both of them giggling, no doubt at some girly thing he wouldn't understand. Despite the small fortune he had spent on dresses for his mother and Alexis and his ex-wives over the years, he didn't really know much about them. So he couldn't really describe the dress that Beckett was wearing, except that it was some green colour that made her eyes look amazing and it was tight in bits and flowy at the bottom and there was skin. There was a whole lot of skin. And that was about when his thoughts went somewhere they never should with his teenage daughter in the room. When he came back to himself a moment (or several) later, the pair of them were at the bottom of the stairs, looking at him in amusement.

"You ladies are amazing," he said, and he could tell by the way Beckett bit the corner of her lip and looked down for a moment, and by the pink blush that diffused over Alexis' features that they appreciated the compliment. "The limo is downstairs," he told them. "Shall we?" he held out one arm to each of them. He pictured arriving at this book launch, Alexis on one arm looking both innocent and alluring, Beckett on the other, a siren, even in dark green. And then she spoilt it.

"We can't arrive together, Castle."

"What? Why not?"

She gave him the patented Beckett look of exasperation. "You know what everyone would think."

Yes, he knew what everyone would think. That's why he wanted them to arrive together. If she was going to look like that, then he was thinking that he wanted every guy in the room to be thinking what everyone would be thinking if they arrived together.

"We've been lucky that the press hasn't figured out we live together. We better not push things," Beckett continued, giving him a determined look.

And there was a warm feeling in the pit of his stomach. Beckett turned and began to put her things into a matching clutch, oblivious to what she had said. We live together. He suddenly felt indestructible. Let every guy in the place think whatever they wanted. Richard Castle knew who Kate Beckett was going home with tonight.

Rick did the usual posing on the red carpet outside the venue with his mother and daughter. He answered some of the reporters' questions, carefully navigating questions about his relationship with the real Nikki Heat. As Beckett had pointed out earlier, the press still remained blissfully unaware of their living arrangements. Although how long that arrangement would continue for, Rick didn't know. Beckett had put in a few applications for apartments while he was away, but thankfully she had missed out on them all. Still, it was only a matter of time before she found someone willing to overlook the fact that her last place had been blown up and grant her application.

Shaking off the melancholy that overtook him at the thought of Beckett leaving, he headed inside to press the flesh and work the room. Some people, like some of editing staff from Black Pawn, the mayor, and the other writers he played poker with, he was genuinely happy to see. Others had to be endured because of their relationship to Black Pawn or their power or wealth.

He'd been there for about ten minutes when he spotted Esposito, Ryan and Jenny in a corner. "Great party, bro," Esposito commented around a mouthful of canapés.

Ryan nodded in agreement, and saluted him with a smoked salmon puff. Rick kissed Jenny's cheek in greeting and they spoke for a moment about their summers.

Suddenly, Rick noticed Esposito stiffen beside him. He was looking across the room, his eyes locked. "Wow," he breathed. Rick figured Beckett had finally arrived, and turned to great her, only to see that the woman who had captured Espo's attention was not a homicide detective, but their favourite medical examiner.

He was totally going to win that bet with Beckett about Espo and Lanie. Hey! Esplaine! He was totally going to use that.

Gina was giving him a dirty look which he knew meant, 'stop hiding with your friends in the corner and smooze' when there was a sudden flurry of activity near the doors. He could hear the photographers outside shouting "Nikki!" and knew he was in trouble. Beckett hated when people called her that.

"Err, I should," he made vague gestures and then shot off to the side of the room furthest from the doors. Yeah, he was a coward. But hopefully his sense of self-preservation would get him through the evening with both ears intact.

He kept half an eye on Beckett all night, trying (and likely failing) to be discreet about it. His attention was captured later in the night though, by the sight of Beckett and Maddie by the large display of Naked Heat books in the middle of the room. As he watched, Beckett lifted a book and opened it to the dedication page. Rick held his breath, waiting for her reaction. He recalled what he had written after his obligatory thanks for the 12th and the people they worked with:

For my Mother, for sending me on my way,

For my Daughter, for showing me the path,

For my Best Friend, for walking it with me.

And for Javier and Kevin, for having our back.

It was always a fine line to walk between trying to tell her how much her sharing her life with him meant, and being cognizant of the fact that millions of people would read it, and she was an inherently private person. So he'd been careful not to use her name, though he hoped she knew that she was the only one he could ever consider his best friend.

She was so much more than that. She was his partner, his equal. She was the one he spoke to about his worries and fears, the first one he wanted to tell good news to, the only one outside his family who he knew would accept him just as he was no matter what.

He watched her read the dedication, heart pounding in his chest. And then she bit the side of her lower lip. A smile she couldn't quite contain spread over her features. There was the barest hint of a blush of her cheeks.

And it took every piece of willpower he had not to rush across the room to her.

She looked up, as though she could feel his eyes on her. Their eyes locked and there was something he had only seen there once before, when they had that dinner with her dad before the book tour. She'd put her hand on his thigh and looked at him and there was something…something he didn't have words for in her eyes. And now it was there again.

It felt like a promise.

And then Madison said something to her, and someone bumped him as they walked past, and they lost eye contact and the moment past. But it was moment.

Castle added it to the evidence list in his head. The case was getting more solid by the moment.

He just wasn't sure what it all added up to yet.

Doctor Matthew Garcia's shift had ended five hours ago. If he was lucky, he might actually manage to leave the hospital within the next four hours. Unfortunately, Dr Matt was not an overly lucky guy.

Standing in crowded emergency department, one still point in a sea of chaos, he allowed himself the luxury of closing his eyes for twelve precious seconds. He took in a deep breath and looked up at the ceiling, breathing out slowly. It was a trick he had picked up in med school, to activate the parasympathetic nervous system and force his body to relax. Even as he exhaled he could hear the sound of a siren coming closer. He shook out his body for a moment, ignored the aching in his feet, the pounding headache, the slight tremor in his fingers. He couldn't remember the last time he ate or drank, but judging by the Sahara in his mouth and the fine tremor he always got when his blood sugar was too low, it had been a while. As always, he ignored it and made his way to the ambulance bay just in time to see the patient unloaded.

"White female, driver in a single car MVA, pinned by the dash board; major crush injuries to pelvis and abdo. Pulseless on arrival. We did ALS protocol; intubated, got access, pushed epi and atropine, got a VT. Shocked and started gels, but she reverted to asystole. It was a difficult extraction with the crush injuries. Further E and A has been unsuccessful. Asystole now for…" the EMT paused, looking to his partner.

"35 minutes," the driver confirmed.

Since the paramedics were maintaining her airway and oxygenating the patient with a bag-valve-mask, Matthew started in on his survey. He looked past where her shirt was ripped open, her bra cut away, the defibrillation pads attached. Not obvious contusion to the head or chest, but beyond that he looked to see her abdomen was a mess.

Matthew felt across her hypermobile pelvis, saw her shortened, internally rotated right legs. Above him, CPR continued. Blood loss from a pelvic fracture was between two and three litres. It was likely that as the front of the car impacted and the back kept moving the patient had been sandwiched between the dashboard and the seat, resulting in a familiar fracture dislocation pattern of the femurs. That could easily cause another four litres of blood loss if the fractures were bilateral. Palpation of her abdomen revealed it was likely she had torn further major blood vessels in the impact. Even with just the fractures she had lost between four and seven litres of blood. And a woman of her size probably only had four and half. If she had torn a major vein or artery she would have bled out internally within minutes.

He ordered them to stop CPR and placed his stethoscope on her chest. He blocked out the background noises: the screaming baby in the waiting room, the crashes as a trolley was pushed over the uneven floors, the beeping of the nurse call bell. He watched closely for the rise and fall of her chest, listened intently for a heartbeat. But there was nothing to see, nothing to hear.

Her heart was not beating because there was no blood to pump.

He took a few seconds to really see her. The woman looked about thirty, with long, dark, curly hair. She would have been beautiful, he couldn't help but think. Amazingly, her face was almost untouched, just a small wound along her eyebrow, most likely an incision from flying glass from a smashed window at impact. Despite the fact that it was a head wound in a highly vascularised area, it was not bleeding.

She had had no pulse for at least thirty-five minutes, but more likely she had died within minutes of impact.

Heavenly Father, he prayed, receive your daughter.

"Time of death, 12:24," he declared.

Thankfully, there was a lull not long after the MVA, and Matthew finally managed to slump, exhausted, into a chair. The slightly stale bread in the break room tasted like heaven, and Matt could have kissed the coffee machine.

"Dr Matt? They found the wallet of the deceased woman, and we've tracked down her medical file from a previous admission. Would you like me to leave it here for you?" Kathy, the emergency department clerk, was like everyone's mother. Sixty if she was a day, she had long red hair shot through with grey, and the kindest eyes Matt had ever seen. She'd made him toast and tea with too many sugars when he'd been run off his feet more times than he could even remember.

He flicked through the file while he finished up his hastily made PB&J sandwich. On the summary page he found what he had been dreading. Under 'Previous Admissions' was a note for NVD – normal vaginal delivery. She had a kid.

He flicked to the contact page and grabbed the phone. Of all the things that sucked about this job; the patients who spat on you or punched you, the long hours, the partners who broke up with you because you were never home, the aching muscles, the families who threatened litigation, two things were by far the worst; telling someone they had a terminal illness and telling the next of kin their loved one had died.

But when he phoned the number next to the name listed as next of kin, it said the phone had been disconnected. There was no cell number listed. Looking for a clue, he flicked through the previous admissions to the notes from when she had been in birth suite. He found out she had successfully delivered twins, and gave Kathy the names of the two kids so she could track down their files, hoping the father or another next of kin might be listed in there so he would have someone to call.

The same name was listed as next of kin in each of the twin's files. But one had recently presented to emergency with otits media and someone had obviously checked the contact details, because the phone number – the same number with a New York area code that was in the mother's file – was crossed out and there was a cell number listed instead.

Matt took a deep breath and dialled. The phone answered after two rings.

"Beckett."

Author's Note: I mentioned this story would be different and very AU and I think the direction we're headed in is pretty obvious now. I know it might put some people off, but I hope you'll stick with me. Thanks for the encouragement on the first chapter. I'd love to know what you're thinking now.

Also, I'm a doctor, and I know the ED scene in here is pretty stylised and probably not consistent with policy in the US, since I've never worked there. For any other health professionals reading this, I hope you'll give me some leeway and enjoy it anyway.