She turned down the alley, her heels barely kissing the concrete as she flew through the air in pursuit of the suspect. "NYPD!" she screamed. "Freeze!"

He didn't, of course. They never did.

But it was a blind alley. He had to stop soon. She planted her feet and raised her arms, training her weapon on the suspect's figure with deadly accuracy.

She tried one last time. "Freeze! Castle, on the ground, now!" she shouted, her eyes never leaving their target. Richard Castle stood thirty feet from her, his own gun pointed unerringly in her direction.

Kate Beckett allowed herself half a second to focus and exhale.

Then she pulled the trigger.

Three Days Earlier.

It was her first day back at work and she already missed Castle. Which was ridiculous, considering that she'd only said goodbye to him four hours ago. She remembered the way that he'd looked in his PJs and bathrobe, with his hair adorably mussed and his eyes still puffy from sleep, as he handed her a coffee in to-go mug in the kitchen this morning. He was taking the boys to go and check out schools today, but she needed to get back to the precinct. Today was her first day back at work since Maggie had died, and she and Castle had been awarded temporary custody of Maggie's seven year old twin sons.

Kate came to the sudden realisation that she was staring at Castle's empty chair next to her desk, and coming dangerously close to sighing. Honestly, could she get any more fangirl? She was disgusted with herself.

It was just that they'd spent every hour together for the last couple of weeks. Ok, so every waking hour together for the last few weeks.

She thought of all the nights they'd spent together on the fold-out up at Maggies'. So every waking hour and most of the sleeping ones for the last few weeks.

Not that anything had happened.

So it was perfectly logical that she would be used to his presence, and you know, miss it when it wasn't there.

(She remembered Lanie, months ago, commenting on how interesting it was that living with Castle hadn't made her feel smothered, when normally she had trouble spending more than a couple of hours at a time with the same person.)

(Sometimes she hated having such a good memory.)

(And that Lanie was always right.)

It's just the boredom, she told herself. Which was true. Since she'd been away, Ryan and Esposito had worked with another team, and now that she was back they didn't have any active cases. They'd helped out one of the other homicide teams with combing through a vic's financials this morning, but that had only taken a few hours. Now they were stuck in homicide, waiting for a body to drop.

Kate looked around the room. Esposito was leaning back in his chair, reading a magazine. Ryan appeared to be attempting to balance a spoon on his nose. As she watched he overbalanced and the spoon clattered noisily to the floor. Ryan swore in frustration.

Kate looked over at Castle's empty chair and sighed.

Finally! Kate thought as she pulled up at the crime scene. And then: I can't believe I was actually hoping to get a call about a murder. I'm a horrible person.

Still, that didn't stop her from leaping from the car and hurrying over to Lanie in anticipation. She felt better when she realised that Esposito and Ryan were hot on her heels, and just as eager.

"Don't worry, she's not going anywhere," Lanie said dryly. "Good to have you back though, hun," she added when she saw Kate, her face softening.

"Thanks, Lanie. It's good to be back. What have you got for me?"

The medical examiner led them to the front of a hotel and pointed upward. Caught up in the awning over the main entrance was the body of a young woman.

"Did she fall, or was she pushed?" pondered Ryan.

"Neither," said Lanie. "She was shot multiple times in the chest before she did a Greg Louganis out of the window."

"Hey, it's Castle," said Ryan, pointing.

Kate's heart skipped a beat, the smile coming to her face automatically as she turned in the direction the other detective had pointed. He must have missed me as much as I missed –

She froze, mid-thought. There, in the bookshop window, was a life-size cardboard cut-out of Castle beside a large display of Naked Heat books.

She frowned. He's with the boys today anyway, she reminded herself. And even Castle isn't crazy enough to bring kids to a crime scene. Still, for a second she'd hoped –

Kate looked back over a Ryan and Esposito's smirking faces. "Funny you two," she said. "And just for that, you two get the double joys and dumpster diving for evidence and canvasing the whole block."

As it turned out, Ryan and Esposito's exploits were entirely unsuccessful. It was Lanie who provided a break in the case, finding a piece of paper with an address scrawled on it, clutched tightly within the victim's hand.

It was late afternoon when the three homicide detectives made their way to the address from the scrap of paper. Kate pulled out her cell on the way to call Castle and let him know where they were headed. Not because she missed him. It was just – you know – she wanted him to still feel in the loop, even if he couldn't come in today.

Right, you keep telling yourself that, Kate Beckett, she thought.

It turned out it didn't matter why she called him, because it went straight to voicemail without ringing. Maybe he's in a meeting with a school principle and turned off his phone, she thought, and hung up without leaving a message.

A moment later her attention was solely occupied by the case as they arrived at the address from the piece of paper, and found the door had been forced open. The three of them drew their weapons, and Esposito and Ryan flanked her as they burst into the apartment.

They moved through the trashed apartment quickly and efficiently. The furniture was overturned, with papers strewn about the room. They quickly cleared the lounge and made their way to the door at the rear of the apartment, presumably leading to the bedroom.

The sound of breaking glass filled the air. Someone was in the bedroom.

Kate turned to face the other detectives, signalling that she would take point and they should cover her. They made their way over to the door and she kicked it open.

"NYPD!" she shouted, her gun trained on the suspect. "Drop your weapon."

"Hands the air!" Esposito shouted from her left.

"Drop it now!" bellowed Ryan from the far side of the room.

As the suspect turned, Ryan shouted "GUN!" as he caught sight of the weapon in the suspect's hand, and then fired at the perp. The shot went wide, embedding itself in the plasterboard to the right of the suspect's head.

"Whoa," said the suspect, holding his hands up in surrender and glaring at Ryan.

Except it wasn't a suspect.

It was Castle.

"Kate?" he said, surprised.

"Castle?" she asked in confusion, lowering her gun. It was then that she noticed there was a dead girl with a bullet wound on the bed Castle was standing next to. Her brain abruptly stopped working as she tried to comprehend the situation.

Esposito looked at the dead girl on the bed, and the gun in Castle's hand. "Drop the weapon!" he shouted, his gun still pointed at Castle's chest.

"What?" said Kate in confusion. "Guys, it's Castle. It's not what it looks like."

"It never is," said Esposito, his gun not wavering from Castle's centre of mass.

"Okay," said Castle, slowly lowering the gun from his hand to the floor. Kate noticed his hand was shaking slightly. He raised his hands in the air.

"Turn around," said Ryan.

"What?" said Kate. None of this was making sense.

"Castle, turn around," repeated Ryan, Esposito covering him as the smaller detective lowered his weapon and pulled out his handcuffs.

"Wait, what?" said Kate. She turned her back to Castle and unconsciously moved to his side, still standing between him and the detectives.

"Lower your weapon, Detective," said Esposito in a firm voice, and Kate realised she was standing in front of Castle, protecting him, her gun still pointed at a forty-five degree angle toward the floor.

"You guys, it's Castle." As a show of good faith, she holstered her gun.

"Kate, I know. But you see how this looks," said Esposito, relaxing slightly, but leaving his weapon trained on the mystery writer.

"I know. And we'll go through all this back at the station. But we don't need to arrest him for that." Unaccountably, she realised that her left hand was holding Castle's right, their fingers laced together. She didn't even remember reaching out and taking hold of his hand. She unconsciously raised their joined hands as she spoke. "He's not going anywhere, right Rick?"

The writer swallowed loudly. "Right," he agreed.

"So we all just put away our guns, and go down to the station, and Rick will explain all this, and Friday night we'll be out for beers telling the crazy story of how Castle wound up leaning over a dead body with a gun, and Annie Oakley over here nearly shot him." She gestured at Ryan, who had the good grace to blush, the handcuffs in his hands dropping slightly. "But right now, everyone just needs to put their guns away, and no one can shoot Castle, ok?" Was that really her voice? She sounded so panicking and shaky.

Castle obviously noticed. "It's ok, Kate." His thumb traced the back of her hand where they were joined. "Nobody but you is allowed to shoot me, everyone knows that. Ryan and Esposito are just doing their jobs. But now let's all go down to the station and talk about this, ok?"

"Ok," she agreed, and everyone put their guns away and Ryan called for uniforms to come and secure the scene. Once backup had everything under control the detectives and the writer left.

And it wasn't until they got to the car that Kate realised that she still held Castle's hand firmly in her own.

Once they were down at the station, Kate refused to let Castle out of her sight. She told herself it was because she was worried someone would arrest him when she wasn't looking, before she had a chance to straighten this whole thing out.

Which was mostly true. There was also the fact that she was utterly terrified and her whole world was falling apart and nothing seemed real except the feel on Castle's fingers entwined with hers, anchoring her.

So when Castle was taken to the interrogation room for questions, Kate went in with him, glaring fiercely at anyone who tried to get in her way.

"So Castle, how about you tell us the one about how you ended up standing over a dead body with a loaded gun?" Esposito asked, as he and Ryan charged into the interrogation room. The two detectives took a seat at the table, sitting opposite Castle and Kate.

"She was already dead when I got there."

"Right, and how did you know to go there?"

"She called me."

"The dead woman called you and invited you over?"

"Yes." He paused. "Before she was dead. Obviously."

Esposito looked over at Kate, sitting at Castle side. His eyes shifted back to the writer. "What exactly was your relationship with the victim?"

"We didn't have a relationship," said Castle.

"Right. So a woman you don't know just decided to bootie call you in the middle of the day?"

"It wasn't a bootie call."

"But you were in a relationship with her?"

"No! She's an artist. Was an artist.I brought a couple of sculptures from her." He turned to Kate, "you know, the figure of the woman without the face on the shelf on the wall the separates my office from the living room? You love that."

"Castle, be serious." Kate warned.

"So if you weren't in a relationship, why would Ms Santori call you?" Esposito asked.

"She was in trouble."

"Why you? Why didn't she call the police?" Ryan asked.

"She said it wasn't the kind of trouble you could call the police about."

"So why did she call you?" Kate asked.

"Because she knew I had a special relationship with you-" his eyes fell on the two male detectives, looking at the two of them with interest – "err, I mean - with the NYPD. She was hoping I could help."

"Help how?"

"I don't know. She didn't want to talk over the phone. Alexis had just arrived home from school, so I got her to watch the boys so I could go over. When I got to the apartment, the place was trashed. I tried to call you, but my cell was dead. I must have forgotten to charge it last night." Kate remembered trying to call him earlier, and the phone going straight to voice mail. "Then I saw the body and the gun."

"And you, being a veteran of multiple crime scenes – both written and real life – decide to smear your prints all over the gun, and then point it threateningly when the cops arrive?" Esposito asked sarcastically.

The door to the interrogation room opened and Montgomery entered. Castle ignored the interruption and continued.

"Maybe you missed the part where I said she was shot dead. When I heard the noises coming from the next room I thought maybe whoever killed her was coming back. So I picked up the gun to defend myself. It seemed like a very good idea at the time. That's when Kate, you, and Fast Fingers Freddy came bursting through the door."

"Fast Fingers Freddy?" Montgomery asked from the doorway.

"Yeah," said Castle. "Quick Draw McGraw over here shot at me."

"He had a gun!" Ryan defended.

"The wrong gun," said Montgomery. "Slugs were from a .45, Castle was holding a .38."

Ryan and Esposito looked visibly relieved. Kate was annoyed at them for even considering Castle had done this. They don't know him like you do, she reminded herself.

"Castle, you're free to go." Montgomery continued.

"And miss all this! No way," said the eager writer. He turned to Kate. "What's our next move?"

She glanced at the Captain and then her watch. It was already after 5:30. "Home," she said. "Takeout because I can't be bothered cooking. Baths for the boys, one –short – bedtime story, not the War and Peace you told them last night. And then we can talk about what you found out about schools for the boys today and possible links between our two vics." She kept a watch on Montgomery from the corner of her eye. She'd told him when she'd agreed to come back to Homicide that she had different priorities now. He'd promised they would be flexible. This was the first test of that.

The Captain nodded, almost impermeably, and she let out the breath she didn't realise she was holding.

"Good," she said, standing up from behind the integration table.

She felt a tugging in her arm as she stood and looked down.

And found that she'd been holding Castle's hand under the table the entire time.

"We're sending the boys to private school." Castle said the second they got into the car.

Kate felt the annoyance creep up her spine. "No, we're not. We already had this argument."

"Argument?" said Castle. "I prefer the term 'lively debate'. And I lost last time. So we're having it again."

"Castle," she sighed in frustration. "I went to public school. And I turned out fine."

"I'm not disputing that. But the boys are going private."

"You might believe that having lots of money makes someone a better person, but I don't."

Castle glared at her. He didn't often get that angry, and it made her take note. "They had metal detectors at the school I took the boys to see today, Kate," he says. "At an elementary school. This isn't about them 'mixing with the right people' or some ridiculous moneyed nonsense. This is about keeping them safe."

"I'm sure it's a precaution. Besides, you think rich kids don't bring guns to school?" she rebutted. But inside she felt herself waver. The boys went to public school before when they were living with their mom. But this was New York City. How could she live with herself if something happened to them? What would Maggie have done?

"There is a statistically significant difference in levels of school violence between private and public schools in New York," he replied. "What?" he said when her eyebrow rose in surprise. "You think I didn't look into all this when I was choosing where to send Alexis? I didn't just close my eyes and chose the most expensive school in the city."

She forgot sometimes, that he'd been a father a lot longer than she'd been a mom. She went silent, thinking about what he had said.

He took her silence as disagreement. "Why don't we talk about what this is really about?" he asked.

"What is this really about, Castle?" her tone was indignant, but she had a feeling this conversation was about to head in a direction that she didn't want to go.

"Money."

Yep. That was the direction she really didn't want to go.

"I have a lot of money. It doesn't make me happy. Those boys need things, like beds and shoes and an education. Buying those things for them makes me happy."

"Castle, it's not that simple."

"Yes it is! If you were out with Alexis one day, and she was hungry, you'd by her lunch, right? So why can't I buy things for the boys they need?"

"There's a big difference between a sandwich and a $30,000 a year private school!"

"Not to me!" Castle shouted. "Look, I know we don't talk about this, but I'm rich. School fees for me are like coffee change for you. And the boys shouldn't suffer because you're too proud to accept money from me."

Her blood boiled, and she wanted to tell him what he could do with his money. But there was a small part of her that acknowledged that maybe he had a point.

"I'm sorry," said Castle, the anger now gone from his voice completely. "But they're my boys too. And if were really serious about doing this together, then I get a say. They've already been through too much. I just want them to be safe."

"You can't protect them from everything," Kate replied. "We see proof of that every day."

"I know." He sighed. "But I'm going to pay for stuff, Kate. I'm going to buy them things. It makes no sense that we live in a world where I get millions to sit in my safe, warm office and make up stories, and you put your life on the line every day to bring real justice and can barely make a living. But that is the world we live in, and one way to make it fair is for me to help. Besides, you won't let me give you royalties from the Nikki Heat books, even though I couldn't have written them without you. So just think of this as your share of the books going to the boys."

Kate sighed. "The schools were really that bad?"

"The principal's office had bullet-proof glass."

She chewed her lip in thought. It didn't make sense to put the boys in danger, if there was another way. "Tell me more about Alexis' school," she conceded.

"Ballistics are back," said Esposito when Beckett walked into the precinct the next morning. "The slug from our girl who took a drive from the hotel window was fired from the same gun that killed the sculptor."

Kate nodded, thoughtful.

"Only problem," Ryan continued, "is that we can't find any link between the two victims. We asked their friends and family, but none of them recognise the other girl."

"So what do a high school chemistry teacher and an artist have in common?" Kate mused. "Thanks for running that down, guys." She smiled at her partners. "Got you a coffee," she said, holding a tray with three Styrofoam cups.

"Nice," said Esposito, with a nod of thanks. He picked up two of the cups and handed one to Ryan. "So, what's our next move, boss?"

"You boys chase down the phone records, and I'll go visit Lanie, she if she's got anything for us."

Lanie was a bust, but the phone records showed that both victims had called the same number the day of their murder. They chased down the number and found it belonged to a man with priors for theft and assault.

Kate thought they finally had a break, but when they got to the guys apartment they found his body, cold on the couch, bullet holes in his chest matching the calibre of the weapon that had killed the two women.

Kate sighed in frustration. He obviously wasn't their killer. But now she just had another body that made no sense. The guy worked in vending machine repairs. So what on Earth did a sculptor, a science teacher and a vending machine worker have in common?

Their breakthrough finally came in the victims' financials. All three of them had deposits of the same amount from the same bank account, on the same days, going back months. So clearly they were into something together.

Just after six that evening, Kate was in the conference room with Ryan and Esposito, the victims' bank account and credit card files spread on the table before her, when she heard her phone ringing from under a small Everest of paperwork. She dug it out, and couldn't help the small smile that spread across her face at the sight of the caller ID.

"Hi, Castle," she answered.

"Making out on a stakeout. Too clichéd?" he asked.

"What?" she asked. Was he suggesting…

"Nikki and Rook. I was writing earlier while the boys were watching The Lion King again. And, anyway, Nikki and Rook are on a stakeout, and they're waiting for this Russian mobster to make contact with his boss. And, you know, one thing leads to another… but I've been thinking that it's been done, you know? Maybe instead of a stake out they should go undercover." He paused, deep in thought.

"You do realise we have an active case going on? And you're calling me about a fictional Russian mob boss?"

"Oh, yeah. I was calling about the case too. How's it going?"

"Going through financials. I think we might finally be getting somewhere." She looked up, seeing Esposito holding a paper and trying to get her attention. "Hang on a sec, Castle." She nodded to Esposito to go ahead.

"Think we finally got a hit. Turns out all three of our victims have credit card charges from the same club down in the Bowery. Feel like a road trip?" Esposito asked.

Kate glanced at her watch. "No, you boys were here late last night," she said. "Go home. I can go check the club out."

"Ooo," said an excited voice in her ear. "Real life undercover! Can I come? This would be awesome research."

Kate paused for a moment, considering. Castle had been great about missing out on the case, and she wanted some way to make him feel involved. And it didn't hurt that she did her best work with him by her side.

"Alright," she agreed. "I'll come home now for dinner and we can put the boys to bed. We'll see if we can get Martha or Alexis to keep an eye on them once they're in bed and then we'll head out and check out this club."

"You're the best!" Castle enthused.

"Right, I'll see you soon."

"Great. And let me know what you think about Nikki and Rook, because I'm still thinking that-"

"Goodbye Castle," she interrupted, rolling her eyes.

She looked across the table to see the two male detectives smirking at her. "So," said Ryan, raising one eyebrow. "What was Castle saying about making-out undercover? Anything you want to share with the class?"