A/N I don't know about anyone else, but in the past series of Blue Bloods when Frank mentioned that he had taken three years to become a Detective and Danny had taken three years and a half and Jamie responded by saying he's been a Patrol Officer for four years. With Frank also having Jamie investigate the cold case, I think at some point during season 5 Jamie may be made a Detective. So this was created by that thought, and then because I'm also a fan of Castle this turned into a crossover.

This will become a multi-chapter story.


It was Sunday and the Reagans were sat around the dinner table, Jamie was still in shock about the news he had received on the past Monday. His dad was the only one who knew that things were changing for Jamie the next day. Jamie sat quietly sharing secretive smiles with his dad and waited for a good moment to tell the rest of the family his good news.

"Hey kid I was wondering if you could do me a favour?" asked Danny,

Jamie shrugged, "Depends what it is."

"When you're out on Patrol I need you to keep an eye out for a person of interest." Replied Danny as he cut up the meat on his plate.

"I would if I could Danny" responded Jamie,

Danny frowned at him in confusion, "What is that supposed to mean?"

Frank smiled at Jamie, which only further confused everyone else sat at the table. "Are we missing something?" asked Henry, his eyebrows crinkling in confusion at the secret smile being passed between his son and youngest grandson.

"For a family full of people whose jobs are to read between the lines, you all are sure slow on the uptake" chuckled Jamie.

"Once you're done insulting our levels of intelligence. Would you care to share what's going on?!" demanded Danny, as he leaned forward and glared at his younger brother from across the table.

Jamie leaned back in his chair and smirked at the looks on his family's faces. "Starting tomorrow I'm no longer a Patrol Officer but a Homicide Detective."

Silence.

Then the room was filled with the loud exclamations of congratulations. Danny then hushed everyone, "so kid are ya moving precincts?"

Jamie shook his head, "Nope I'm staying in the 12th."

Henry nodded, "I've always heard good things about the Homicide Detectives from the 12th"

"Best Homicide closure rate in the entire city" added Frank, "Captains Montgomery and Gates have made it a fine Division."

"Shame about Captain Montgomery three years ago" mourned Henry,

Frank nodded in agreement, "But Captain Gates has continued to ensure the Division is the best."

"If I remember correctly Victoria Gates was, and is, one of the best Police Officers this city has ever had." Henry commented.

Danny choked on his drink, "Victoria Gates?! Captain Victoria 'Iron Gates' Gates? Formerly of I.A?" he shook his head, "it's a good thing you're a stickler for the rules kid. I'd hate to see what would happen to ya if you were-"

"More like you?" smirked Jamie,

"Watch it kid" warned Danny teasingly.

Henry laughed and then asked Frank, "Kevin Ryan works in the 12th's Homicide Division doesn't he?" Frank nodded.

"Whose Kevin Ryan?" asked Sean,

Danny turned to his youngest son and replied, "He was a good friend of your Uncle Joe's. They went to school together, went through the Academy together and spent their Patrol years working out of the 12th." Sean nodded and then went back to eating his dinner.

Danny then looked over at Jamie and raised his glass, "To my little brother, who was a great Patrol Officer and may he be an even better Detective."

Everyone toasted to Jamie and they all secretly breathed easier knowing that Jamie was no longer spending all his tours out on the streets.


It was Monday morning and Jamie felt strange driving to the 12th precinct in a suit instead of his everyday clothes before changing into his uniform. Wearing his uniform used to be an everyday affair, now it was going to be something that was rare. He found himself almost walking to the changing room that held his old locker. But all his stuff that was in his locker was now in a bag he was carrying that was going to be placed in a new locker.

He walked over to the elevator and pressed the button for the fourth floor. As the doors pinged open he took a deep breath. He heard his phone go off and he saw he had a text from Danny.

Good luck, I know you'll do great. Meet you after tour at the usual bar.

Jamie smiled, then pocketed his cell phone before walking into the ball pen.

"Hey Jamie!" he turned to see Kevin Ryan walking towards him smiling, "I heard it was you who was the new rookie."

He smiled and greeted Ryan's partner Detective Javier Esposito (who he had meet a few times in the past and most memorably when he had taken Esposito and Ryan home after being captured by a suspect three years ago *) and his other colleagues Detective Kate Beckett and the crime novelist Richard Castle.

Ryan then led Jamie to Captain Gates' office and smiled, "It'll be great working with you"

"You to" smiled Jamie, he then knocked and entered Captain Gates office.


Jamie came out of the office completely terrified of his new Captain, he knew being the Police Commissioner's son that she was going to be keeping a close eye on him to ensure he didn't use his last name for any personal gain. He didn't expect anything less, his dad had told him when he first joined the force that he was going to have a lot of people watching him.

He was introduced to his new partner Detective William Harris, he had been a Homicide Detective for ten years and Jamie liked him already, he was close in character to Renzulli so Jamie knew Harris was a guy he could trust with his back. Harris showed him around the fourth floor, and in the break room he came across the most expensive coffee machine he had ever laid eyes on. Apparently it was a gift from Castle a few years back, so Jamie took out his phone and sent a picture to Danny. His brother's reply wasn't for polite company. Harris also showed him his new locker and then took him to his desk. His desk faced Harris' and just to his left was Ryan's desk, Ryan smiled and waved as he got up from his chair and left to go and question a suspect.

Jamie spent the day doing paperwork and getting to know the people in the Division. At lunch Harris took him a nearby sandwich take away, a place Jamie had been meaning to try but all his lunch breaks on Patrol were spent somewhere else in the city.


After lunch Jamie was doing some more paperwork when Castle came and sat himself in the chair beside Jamie's desk.

"So you're a member of the famed Reagan Police family" stated Castle,

"Yep" chuckled Jamie, "But don't say that to my sister, she gets offended when people forget that she's not a cop but an Assistant District Attorney."

Castle grinned, "So did you always want to be a cop?"

"Castle stop interrogating my rookie!" ordered Harris, but Jamie could see the small smile on Harris' face.

The writer shrugged and then turned back to Jamie expectantly, Jamie smiled. "Kinda. But I did graduate Harvard Law before going to the Academy."

Castle widened his eyes in surprise and Harris exclaimed, "You went to Harvard?!"

Jamie nodded, he slightly blushed seeing all the nearby Detectives staring at him in shock, expect Ryan who smiled at him. Jamie figured Joe must have told Ryan about his going to Harvard.

Castle got over his shock and then asked, "Is this your first day as a Detective?"

"Yeah" confirmed Jamie, confused as to what Castle was fishing for.

"Any good stories from your time as a Patrol Officer? Beckett, Esposito and Ryan won't tell me about their time spent as Patrol Officers." Complained Castle.

Jamie grinned, "A lot did happen."

Castle edged forward in his seat, "Well go on!"

Jamie sat back in his chair and gently tugging on his tie he thought back on all that had happened to him in the past four years. "Well in my first few weeks on the job my TO had me arrest someone in a hot dog suit." Castle burst out laughing and Jamie noticed some of the other Detectives listening. "There was also a lady protesting about her cheating ex-husband with a blow up pig, which my TO made me deflate and then a couple of days later we get called back there and she was protesting again, but this time she had a real pig with her." Jamie chuckled along with everyone else remembering Renzulli's order to deflate the pig.

"I bet you got in some sticky situations" stated Castle, he had worked with Detectives long enough to know the job didn't come without its risks.

Jamie nodded, "I've been pushed down stairs, nearly had some alone time with a Mob boss-"

"Wait a second! A mob boss? Explain!" demanded Castle.

From the corner of his eye Jamie noticed Ryan leaning forward interested. "Two years ago I was in a bar with a few other Officers in plain clothes and tasked with making sure there was no underage drinking. Then I ended up helping this guy called Noble, who it turned out was a member of the Sanfino crime family. A family O.C.C.B had had trouble getting Intel on for years, so I went undercover."

"Wow" whispered Castle in amazement, "And you were only in your second year on the job?" Jamie nodded and a few Detectives whistled in appreciation.

"You've always been at the 12th precinct?" asked Castle. Jamie nodded and Castle continued, "So were you involved in the situation at the Bitterman houses last year?" Again Jamie nodded, "So you must have known Vinny Cruz"

"Castle!" warned Ryan sharply, Castle turned to Ryan in confusion not realizing he had said something he shouldn't have. Even Harris shook his head at Castle, and then looked over at his new partner. Ryan looked over at Jamie in concern, he was aware of what had happened to Jamie at the Bitterman houses last year.

But Jamie had frozen and the bullpen in front of him had faded away.

"10-13! 10-13! Officer's been shot! Bitterman houses, main quad!"

Firing his own weapon, reaching Vinny pulling him up by his jacket "Vinny get up man! Get up come on! Come on get up!"

Pulling Vinny behind cover muttering that he had Vinny and that it was going to be ok. Pressing his hand into Vinny's wound.

"You're gonna be ok. Look at me! Look at me you're ok alright? Hey don't go anywhere, stay right here with me ok? Fight! Come on fight! Hey Vinny come on! Stop smiling! Hey look at me man!"

Vinny blinking up at him and saying, "it's ok, hey it's ok Reagan. I told you, I told you this is the end"

"What?"

"It's the end. It's ok"

"Jamie?"

He shook himself and found himself looking at a small group of concerned gazes, he looked back at Castle and said, "Vinny was my partner."

"Oh I'm so sorry!" exclaimed Castle, he began tripping over himself to apologize.

Jamie chuckled, the memories already beginning to fade, "It's alright, don't worry you didn't know."

"Ryan did! Even though he's only met you a few times!" argued Castle as he looked back at his friend.

Jamie shook his head as Ryan commented, "I knew Jamie's middle brother Joe. We were friends growing up, me and Joe always kept a close eye on Jamie here. So once he joined the 12th I just kept tabs on him in case he needed anything." Ryan missed the look Esposito had directed at him.

"Oh" said Castle, he turned to Jamie, "I'll leave you to your paperwork, but your welcome to join us at the Old Haunt tonight if you want, I know the owner." Grinned Castle.

Jamie smiled, "Thanks for the offer, but I'm meeting my brother Danny for a drink later."

"Fair enough." Nodded Castle, "See ya around Jamie."

Jamie smiled at Ryan and Esposito and went back to his paperwork and chatted with Harris.


Jamie walked into the bar and found Danny had already got them some drinks. Jamie dropped onto the bar stool and took the spare bottle.

"Thanks Danny." He smiled,

"No problem kid. So Detective, how did your first day go?" asked Danny as he took a sip from his beer and looked at his brother.

"It was great!" grinned Jamie.

Danny nodded as he smiled, "That's good. So who's your new partner?"

"William Harris" replied Jamie.

Danny nodded again, "I've heard good things about him, glad he's your partner."

"You been keeping tabs on me?" questioned Jamie,

Danny shrugged, "Not all the time, I've only done it when you graduated the Academy and was assigned to the 12th and when you told us about your promotion. Just want to make sure my brother's back is covered by the best."

Jamie smiled, "Well you don't need to worry. Harris is a lot like Renzulli. No doubt I'll be fine."

"Good" commented Danny.

They then began talking about anything and everything, when Danny raised his bottle. "To you Detective Reagan"

"And to you Detective Reagan" grinned Jamie. They clinked their bottles together and took a gulp from their beers and Jamie was sure this was the beginning of something great.


A/N I have an idea what I'm going to do in chapter 2, but after that any prompts (e.g. funny situations or angsty ones) would be most appreciated.

* Reference to chapter 3 in my Castle story Making it home.