Richard Castle surveyed the contents of his wardrobe. How was it possible that he had a walk-in closet bigger than some studio apartments, and yet had nothing to wear?

Beckett was working a case with a dead artist, high school science teacher and vending machine operator who were somehow linked. Their only clue was that all three had been to a club in the Bowery on the same nights.

So Castle and Beckett were headed on some real life undercover to the club.

And he had nothing to wear.

He needed something that was young and hip. Oh God, did young people still use terms like 'hip'? he wondered. Fresh, he thought instead. I need an outfit that's young and fresh.

Obviously, he needed to look devastatingly handsome, so Kate would stop seeing him as the nice guy who slept in the bedroom on the floor below her, and starting thinking of him as the total hunk who slept half naked only thirty steps from her own bedroom. Did young people still use terms like hunk? But, just as obviously, he didn't want to look too good and completely distract her from the case and the whole purpose of going to the club tonight.

Yeah, right, he thought. Like I've got a chance in hell of that happening.

Still, Richard Castle was nothing if not an optimist.

He reached for his green button down. Kate's favourite colour was green. But then he caught sight of the blue sweater next to it. Alexis said the blue brought out his eyes. His hand hovered between the two. Maybe he should go for black? He didn't know what kind of club they were going too, but black was always in, right? Plus, black sort of fit with being undercover. What if they were chased out of the club by the murderer and had to hide in the dark of night? That green button down would stick out like a sore thumb.

On the other hand, how was he supposed to stick out of the crowd in the club and make Beckett fall in love with him if he was wearing the same boring black jacket that she saw him in all the time.

He reached for the green button down with one hand, and then picked up the red, fitted shirt he had put down earlier because it was too flashy. He turned to the full length mirror and held the red shirt over his body. Then he swapped it for the green. Red again. Then green. Red. Green.

After 30 seconds of alternating the shirts, he realised he looked like flashing lights at Christmas. He let out a groan of frustration.

Maybe the blue...

"Castle!" he heard Beckett call from the lounge.

"Yeah?" he called back.

"Where are you?" she called back, her voice sounding closer. Rick heard the sound of Beckett's heels making their way through his office and into his bedroom.

"In the closet," he called back.

Kate's pealing laughter rang out as she appeared at the entry to the walk-in closet. "I always suspected as much," she giggled. "I've seen those looks you shoot Esposito."

"What? Esposito is totally not my type!" he defended.

Kate laughed again.

"And I'm not gay!" he added as an afterthought.

"Well Castle, you're the one shouting about being in the closet. It's the 21st century. You don't have to hide anymore." Kate replied in a mollifying tone.

Sometimes, the best defence is a good offense, Castle mused. He took a step toward her and dropped his voice half an octave. "My dear detective, I am not gay, and would very happily prove that to you at your earliest convenience." He shot her his most ruggedly handsome smile.

Kate broke eye contact, talking a step back. She glanced at the shirts clutched in each of his hands and shook her head. Reaching past him she grabbed the black shirt he had earlier rejected. "I'd go with black," she advised. "Ready in five minutes?"

Castle nodded, disappointed she hadn't taken the bait. Oh well, there was always tonight.

"Right, so, what's our angle?" Rick asked.

"Angle?" Beckett asked distractedly as she eased the car into a vacant space about two blocks from the address of the club.

"You know, for the club? Oh, I know! It's our third date, and I'm bringing you out here to impress you. If anyone asks where we met, we'll say at work. We can say we're Lawyers. No wait! That might make them suspicious, if they're doing something illegal. Hmm… we could be teachers. I teach English, obviously. You take Gym. No wait! Russian! Your name is Svetlana and you're the new Russian teacher. You can do your accent again."

"Castle, I don't think this is the kind of undercover that requires a convoluted back story," Kate replied as she undid her seat beat and got out of the car.

They began walking down the street toward the club. They hadn't made it the full two blocks before Beckett couldn't stand Castle's pouting any more.

"Ok," she conceded. "We'll have a cover story."

Castle grinned.

"You can be my brother," Kate smirked.

Well, that certainly shut him up.

There was a lady with a large snake curled around her bikini clad body. On stage, a stripper gyrated to a thumping base soundtrack. A man on a smaller stage in the corner was juggling knives, and Castle turned toward the bar just in time to see a bartender breathe fire across the room.

"This place is amazing!" he breathed. "How have I never been here before?"

"You think this is good, you should see some of the clubs I go to, Castle," Kate said.

Rick's jaw hit the floor. "Wait, what?!"

He turned to Kate, but she was already making her way toward the bartender, looking for information.

Beckett better not be holding out on me, he thought. If she knows cool clubs she isn't taking me too…

His train of thought trailed off as he noticed Beckett talking to the bartender. She laughed, flicking her hair back.

Wait, is she flirting? thought Castle with a mental frown.

Kate lent across the bar, smiling at the (totally sleazy slimeball and in no way attractive) bartender, straightening her shoulders slightly to bring attention to her cleavage.

The (totally sleazy slime ball and probably a serial killer) bartender smiled in appreciation.

She obviously needed rescuing. "Don't worry Svetlana, I'm coming!" he shouted, dashing across the room.

Castle unlocked the door to the loft, Beckett close behind him.

"Hey, Alexis," said the detective, closing the front door behind her. "Were the boys any trouble?"

The teenager looked from the couch were she was reading through a large textbook. "Nope. They slept the whole time you've been gone. How was the club? Get any leads?"

"Maybe," said Kate, struggling to prevent a yawn. She flopped down on the couch next to Alexis.

"Want a drink?" Castle offered as he made his way to the kitchen.

"Nah," said Kate, resting her head back on the couch, her eyes sliding shut. "I'm beat. I think I'm going to head off to bed."

Castle took a bottle of water from the fridge. "I just don't get it," he said. "A metal sculptor, a high school science teacher and a vending machine salesman walk into a burlesque bar and suddenly wind up rich."

"And then dead," Kate pointed out.

"It sounds like a bad joke," Castle noted.

"You'll figure it out," said Alexis.

Kate nodded, her eyes still closed in exhaustion, heading lolling back against the couch. She should get up and go to bed. Everything would be clearer in the morning. But the couch was so comfortable…

"Alright you. Bed." Castle said, nudging her slightly.

"Don't wanna," she mumbled. Her bed was all the way upstairs. Couldn't she just sleep here?

"C'mon Kate," said Castle, his voice gentle. He grabbed her arm and helped pull her into a standing position. "Don't make me carry you," he threatened.

Kate half walked, half stubbled toward the stairs. As her hand met the banister, she looked back the couch. "Bed time, Alexis?"

The redhead held up the textbook in her arms. "I think I'll study a bit long for my chem test on Friday."

"'Kay," mumbled Kate. "Don't stay up too late." She smiled and wished Castle a good night before making the heroic trek up the stairs to her room. She poked her head into the boys' room, seeing them both fast asleep, and then continued on to Martha's room. Well, my room now, she thought sleepily.

The moment her head hit the pillow, she was fast asleep.

The following morning chaos reigned in the loft. Castle had got the boys enrolled at Alexis' fancy private school the day before, and today was their first day. Which meant hurrying the boys through breakfast, and getting them dressed and trying to pack all their school things into bags, before rushing to get them to school on time.

Kate drove them all in her Crown Vic and couldn't believe how strange it felt. Six months ago she was driving around the city all alone, and now she had Castle in the passenger seat, and three kids in the back, making the school run.

It was almost unbelievably domestic.

Traffic was horrible, but they managed to get to the school before class started. They found the boys' classroom and introduced themselves to the teacher, a kind young woman named Ms Aldrin. Kate checked four times that the boys knew where to meet them after school, and then Ms Aldrin was ushering them off to their seats, and Kate and Castle were on their way to the 12th.

As wonderful as it was to have Castle back by her side, Kate couldn't help but worry about the boys as they drove away from the school. What if the other kids asked about why they had started at a new school? Or asked about the boys' parents? Would they be teased for their poor background in a school full of the sons and daughters of wealthy New Yorkers?

They parked in the undercover garage of the precinct. Kate headed straight upstairs to the homicide floor while Castle detoured down the block to the Starbucks on the corner for their morning caffeine hit, since they hadn't had time to fit in a coffee with the pandemonium of the morning school preparations. Kate wondered if every morning would be this bad and was exhausted all over again.

When Castle emerged from the lift at homicide, he was greeted with a very familiar scene. Ryan and Esposito were sitting at their desks, holding phones to their ears. Both seemed to be on hold, but they each greeted him with a "welcome back" and a fist bump as he walked past.

Beckett was in her usual spot before the murder board, leaning against her desk. She held a white board marker in her right hand, tapping it idly on her chin, her brows furrowed in thought as she stared at the writing before her.

He fell into place at her side, handing her a cup.

"Thanks," she murmured, smiling. She took a sip of the liquid and let out a contented sigh.

"So," said Castle. "A metal sculptor, a high school science teacher and a vending machine salesman walk into a burlesque bar and suddenly wind up rich."

Kate remembered his words from last night. "And then dead," she finished.

"Science teacher, artist, salesman," Castle was muttering under his breath. "Wait! They were cooking meth! It's just like Breaking Bad. They all need money, and after a few drinks, the science teacher says 'Well we could always make meth' and then suddenly it seems like a good idea."

"I don't know," Kate mused. "Lanie said the bodies didn't have any traces of drugs."

Castle slumped a bit in defeat. "Maybe not drugs. But they were making something illegal that was making them a lot of money."

Kate paused, rolling the words around in her head.

"That's it!" she said.

"I know," said Castle, dejectedly. "If only we could figure out the illegal thing they were making. We can't go to a judge and say 'he dude, these guys were doing something illegal, just give us a warrant and we'll get back to you on what it is'."

"No, Castle, you said it. "They were making something illegal that was making them a lot of money. A metal sculptor, an artist and a vending machine guy. They were making illegal money. It's a counterfeit ring."

"An artist, a metal sculptor, and a salesman to supply the bills. Of course. The only thing missing…"

Is ink. Kate though. Then she remembered the owner of the club they went too. A tattoo artist.

Kate and Rick turned to face each other. "I know who the killer is!" they said in unison.

Behind them, Ryan and Esposito rolled their eyes.

As they pulled up in the car park beside the club, Beckett turned to him. "It's no use asking you to wait in the car, is it?" she asked.

"Please," he scoffed.

"Just…don't get shot, ok?" she replied.

He smiled, reaching out his hand to touch hers as it rested on the seat. "I won't if you won't," he promised.

They smiled at each other briefly, then got out of the car. Ryan and Esposito made their way over from their car behind them. "We'll all go in together?" asked Ryan.

Beckett nodded and the foursome made their way to the entrance of the building. Kate tried the door and found it open. Inside, they could hear the noise of someone packing hurriedly.

They recognised the voice of the tattoo artist, "Hurry up," she was shouting. "We gotta get out of here now!"

The three detectives and the writer made their way noiselessly to the back room. "Freeze," yelled Beckett, her gun pointed at the woman who was stuffing cash into a large bag.

The suspect dropped the bag, screaming for her husband to help. Esposito made his way to the doorway at the other end of the room, his gun drawn, looking for the husband. Beckett kept her gun trained on the woman as Ryan pulled out his cuffs.

Castle heard a faint scuff from behind and turned to find the suspect's husband emerging from behind a stand of shelves, the gun in his hands pointed at Kate.

"Gun!" he screamed, and dove on Kate, just as the man fired. The bullet missed them both, but they landed heavily on the concrete floor. In the moment it took for him to make sure neither of them were hurt, both the woman and the man had made a run for it.

"Damn it!" said Kate. "I'll go after her. Wait here, Castle."

"What if they come back?" said the writer in fear.

Kate looked at him for a moment. She pulled her spare gun. "Here," she said, handing it to him.

He nodded his thanks, and she ran from the room.

Rick stood in the empty room, his ears trained for the sound of Beckett catching the suspects. But what he heard instead was the sound of heels on the concrete. He turned and saw the tattoo artist running out the back door of the club, the bag filled with money in her arms. She must have given Beckett the slip and doubled back.

"Stop!" he shouted, giving chase.

He could hear Ryan and Esposito's shouts from outside. "Where did he go?" Esposito was shouting.

"I think he went around this way," Ryan shouted.

"I don't see him," Esposito shouted.

Suddenly someone fired at him. He ducked and turned, running for the door he had seen the woman disappear out of.

He emerged in an alley way, catching sight of Kate, her gun held in her outstretched arms.

"NYPD!" she screamed. "Freeze!"

He started to lower his gun, and then caught sight of the woman he had been perusing at the other end of the alley. She had a gun pointed a Kate's back. He brought the gun up, tried to get a clean shot.

"Freeze! Castle, on the ground, now!" Kate shouted, her eyes still trained on him, her gun pointed unerringly in his direction.

No, he wanted to say. I'm not shooting you, she's behind you.

But there wasn't any time.

Any second now, the tattoo artist was going to fire her gun and shoot Kate in the back. Of course, if he didn't lower his gun, Kate was going to shoot him, without realising that he wasn't trying to shoot her.

He could very well die today.

But if he didn't, Kate Beckett would.

And that was unacceptable.

He focused on the woman at the end of the alley and fired. A quarter of a second later, Kate fired back.

Castle heard a noise from behind him and turned. The male suspect they had been chasing was lying on the ground behind him, a bullet in his shoulder. His eyes focused on the gun in the suspect's hand. The guy had been just about to shoot him. And Kate had saved his life.

Thirty feet away, Kate had turned and noted the female suspect behind her that Castle had shot. Her eyes went wide as they saw the gun in her hand.

If it wasn't for Castle, she would have been shot in the back, she realised.

For a moment, Kate and Rick turned and locked eyes. Both of them were breathing heavily in relief. Ryan and Esposito emerged from the building and took custody of the two suspects.

Castle exhaled harshly again, and locked eyes with Beckett. He tilted his head to the side, silently asking if she was ok.

Her eyes went wide, communicating her shock, and then she nodded her head once in thanks. She lifted an eyebrow, clearly asking if he was ok too.

He run a hand through his hair, nodding.

Well, nothing like going back to work with a bang, he thought.

"So they were all sweet with the counterfeiting operation, until the loan shark found out and wanted to take over the deal." Castle explained to Montgomery.

"And the club owners weren't too keen on that." Kate continued.

"Turns out, the tattoo artist had a record," said Castle.

"Did a nickel for running over her boyfriend," Kate interjected.

"So when she wasn't keen to give up the operation, she figured she'd just bump off everyone who stood in her way." Castle finished.

Montgomery smiled. "It's good to have you back," he said with a smile. "That was a great story."

Castle and Beckett looked over at each other and smiled.

"How about later, you tell me the story of how Castle got you gun?" he asked.

"Oh!" said Castle, looking at his watch. "Is that the time? I better go pick up the boys and Alexis from school." He headed for the door.

"You better head off too, Detective," said Montgomery, nodding at Beckett.

"Sir?" said Kate, smiling. After the day she'd had, finsihing early sounded like Heaven.

"Just make sure you take the IA paperwork with you. I expected it to be completed and on my desk first thing in the morning."

"Yes, Sir," said Kate, although the smile looked at little more forced this time.