Hello :) this is my first Blue Bloods fic, so if anything is OOC I apologise. I hope you enjoy the story, this is the first chapter of a multi-chap fic. Reviews/comments/constructive criticism are greatly appreciated. Hope you enjoy the story!

Disclaimer: I do not own Blue Bloods, only my OC Kate.

Kate picked at the food on her plate, more interested in observing the other occupants of the table than her roast dinner. She reclined in such a casual manner, twisted sideways with one heel of her leather boots pulled up onto the edge of the dining chair, that it bordered on being disrespectful. No one at the table commented though.

"So how's the case going, Danny?" Frank asked too casually, trying valiantly to act normal, the slight tension in his mouth would have given him away though, even without the uncomfortable silence at the table. Danny glanced up from his plate and then quickly down again, it was the wrong question to have asked.

"Not too good, our main suspect has an alibi. We know it's bogus but with 12 people swearing he was at a party at the time of the murder and no evidence tying him to it we got nothing."

"If there's no evidence how do you know he did it?" Jack asked tentatively, knowing how his father could get when he was on a tough case. Danny stabbed a piece of broccoli much harder than necessary before replying.

"Because the dead guy was going to testify against my suspect when he is brought to trial. The department's been building a case against him for seven months. It's not a coincidence our witness was killed now. If this guy didn't do it he ordered it, but I've got nothing on him."

"And without that testimony our case is nothing but circumstantial." Erin interjected tersely.

"If he was that important why didn't you protect him?" Everyone looked up at Kate, she had barely said a word to them until now, but her voice when she did speak was strong and clear. It was becoming clear her reserve had nothing to do with shyness. Erin turned to answer her but the gaze she met was unnervingly direct. Taking a moment to compose herself, she replied in what she hoped was a measured tone.

"We wanted to, but the victim refused our help-"

"Arrogant." It was a statement, not a question, and once Kate was finished she abruptly looked away, effectively dismissing the older woman. Ruffled by the bluntness of the much younger woman Erin didn't reply and the table lapsed into awkward silence once more. Nicky caught the eye of the boys across the table.

"Come on guys, let's help clear." The other kids all stood and started picking up dishes. Henry and Linda followed them and Frank, Danny, Erin, Jamie and Kate were left at the table. Frank effected an air of relaxation and tried to casually suggest they all go and relax in the sitting room. A hint of a smirk tugged at the corner of Kate's lip as she took in how unsure they all were before pinning a sarcastic smile on her face.

"Okidoke gramps." She stood and sauntered over to the couch, her developing hips swayed as she walked. It was clear to Frank she was hyper aware of the effect of her every movement, of every expression, of her every word. When not putting on a specific act though her default mode was serious, her mouth grim and eyes dark. It was incongruous with her young, pretty features and adolescent figure. Her hair was long and blonde, and her eyes piercingly blue. Kate settled herself at one end of the couch and the others awkwardly followed her lead.

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In the kitchen no one really spoke apart from about the cleaning up, until Nicky eventually broke the stifling atmosphere.

"So are you gonna explain to us what is going on with Kate?" The adults looked awkwardly at each other for a moment.

"Well, it's like we said-" Linda started.

"You said she was Uncle Joe's daughter, but you haven't explained how that's possible, or where she's been, or what's going to happen now."

"And that we have to be patient and get to know her." Sean interjected quietly.

"How can we get to know her? We barely even see her. Where does she go all the time? The boys already told me she hasn't stayed at your house, and she hasn't stayed here either, has she? What does she do? Where does she go? Where did she come from?" They had all abandoned the cleaning by now.

"We don't know kids," Henry said simply, "but she's family and we'll figure it out. Let's just be glad we have her."

"We are glad, but it doesn't mean we don't have questions. How do we know she's part of the family? And how did Uncle Danny and Grandpa find her?"

"Well, the truth is we didn't find her, she found us." Henry said quietly. The three kids looked shocked, the adults had agreed not to say anything until they had a better idea of what was going on, but it had been two weeks and they were no closer to answers, it wasn't fair to keep them in the dark any longer. "We know she's part of the family because your Grandpa had a DNA test done."

"Now that's enough for now, let's get these chores done and then we can go do something fun, eh?" At Linda's command they got back to work, but no one really felt like having fun.

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"So we wanted to talk to you Kate." Danny said, strain evident in his voice despite his efforts to conceal it.

"Of course you did." She sounded bored, and her pose slumped on the sofa made it look like she was just an ordinary, brusque teenager, but a sharpness in her eyes gave her away to Frank. He showed no sign of having noticed this, but filed it away for future reference as he sat forward with his hands clasped in front of him. His eyes were bright, and he was frowning slightly.

"Kate, you came to us a little over two weeks ago. As you know what you had to say was a surprise to us all, a wonderful surprise of course, but we had no idea-"

"I existed?" Kate interrupted Frank in a clipped tone. "Don't worry yourself Gramps, you couldn't have known. Where are you going with this?"

"Well, Kate, what I'm getting to is we know nothing about you. We want to get to know you but you're not making it very easy for us." Erin chose this moment to jump in.

"We don't know where you sleep at night, where you go to school, or even if you do go to school." Erin's voice took on a slightly warning tone despite herself.

"Speaking of school, exactly how old are you, kid?" Danny tried to make the question casual, but Kate just raised her eyebrows and smirked a little. After a moment with no answers Jamie continued in his patient, reasonable voice, hoping it would get through to her.

"Look, if you're not ready to tell us about yourself yet we get it, but what we really wanted to ask you is, would you consider moving in with one of us?" The words tumbled out of his mouth. "We have no way to reach you, we don't know if you're safe, who you're with." Kate chuckled at that despite herself, looking away from them for a moment before turning to hold Jamie's gaze. "We can guess that wherever you've been up until now hasn't been good, but we want to change that. Danny and Linda have a spare room, so do Nicky and Erin, so you could live with your cousins. Nicky's around your age, the two of you could really get on well, and the boys are great kids. Or you could live here with Grandpa and Pop, it's up to you."

"We want you to be a part of this family." Frank said, emotion tightening his voice. Kate looked around at them for a moment, taking them in, before standing abruptly.

"Thanks, but sorry gang, I do my own thing, see you around." She walked over to the foyer and started putting her coat on, a khaki top coat, over her red and blue lumber jack shirt and jeans. Frank followed her, leaving the others to fidget in the lounge.

"Kate, don't write the idea off just yet, think it over, the offer doesn't have an expiration date."

"Whatever, Commish. Thanks for dinner." She pulled on her tan leather backpack and was gone out the front door. Danny, who had started to approach from the lounge, went to follow her, but Frank stopped him.

"Dad, we can't just let her -"

"It will do no good to follow her, she isn't going to do anything she doesn't want to."

"We at least have to find out where she's going!"

"We can't, I know, I've tried!" Frank said irritably before looking away. "After she showed up that first time I've tried to have her followed a couple of times. She always knows and loses them. She just disappears!"

"That's impossible," Jamie said from behind Danny, he and Erin had joined them by now.

"And yet she does it. If it weren't for the boot marks on my couch and the three DNA tests I had run on her I could hardly have believed this girl is real . . . Look, I think the more we try and pull her in, the more she'll keep her distance. We're just going to have to wait for her to come to us."

"If she ever does." Erin said grimly.

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Monday morning was as just as unpleasant as Danny had been expecting. The station was too busy, too loud, and he was exhausted. He had snatched a couple of hours sleep after having staked his suspect out for most of the night and the only thing to show for his trouble was an over familiarity with the guy's smoking habits. He'd done nothing all night apart from have one on the hour, every hour, outside the doors to his luxury apartment building. Either the guy didn't like the smell of smoke in his penthouse or he knew they would be watching and was taunting them. Didn't take a genius to work out which. His name was Marcus Brooks, a former trust fund baby, who was used to getting his own way, regardless of what it took to get it. The guy had made millions in illegal stock trading, and now that he was actually going to be punished for the first time in his life he thought he could just kill a guy and it would all go away. Not with Danny on his ass though. He had to come up with something to nail the SOB on, but with his witness dead, a rival trader who'd rolled over on Brooks in order to save himself from charges, he had nothing to go on. He rubbed his eyes and sipped at the awful coffee in a paper cup at his elbow.

"Morning sunshine" Jackie quipped as she joined him at their desks.

"Ha ha, how'd it go with the CCTV search at the time of our murder?"

"Got some footage of a big guy in a baseball cap and dark jacket walking down the street outside the alley the vic was found in around the TOD but nothing to ID the guy or even say he was involved."

"Great, so we got nothing."

"Pretty much. Oh, this came for you this morning." Jackie handed him an envelope, Danny opened it without much interest, pissed at the progress on his case. As he began to read his face rapidly changed into an expression that could only be described as the physical equivalent of 'what the hell'.

"Danny? What is it?" He showed her the letter wordlessly. It read:

Search the area around the scene of the murder of Darren Forrest again. Pay special attention to searching the drains 6 blocks east. You will find the murder weapon in a white plastic bag. Rush through forensic tests on it, the man it will lead you to is leaving the country tomorrow. I am sure you will find what he has to say useful in the case against Marcus Brooks.

Danny and Jackie stared at each other in disbelief.

"Do you think it's a joke?" Danny didn't answer for a moment.

"No, the details are too specific. But who the hell could know this stuff?"

"Should we go to the sarge?" Danny thought carefully before replying.

"No, if we do find something this could call the evidence into question, we could be accused of faking the evidence, and this letter, to create a lead. Let's just order another search by the uniforms, we're at a dead end anyway. We've decided we'd give widening the search parameters a shot. Nothing unusual about that. If we find something, well, it's just good luck."

"Ok, I can run with that."

"You've got a friend in forensics, right? See if you can get her to run this and the envelope, try and find something to identify our mystery informant. Keep it between us though."

"Will do." Jackie walked off, leaving Danny at his desk looking troubled.

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Miles Williamson hadn't been expecting them, if the sight of him wrapped in his shower curtain was anything to go by. His bags were packed and by the door, in half an hour he would have been on his way to the airport to catch his early morning flight. Instead he found himself trying to put his pants on whilst cuffed, Jackie waiting outside trying not to laugh whilst Danny watched him struggle. Eventually he ended up cuffed to the interrogation room table, trying to look intimidating in spite of the debacle the officers had just witnessed.

"You gonna tell me why I'm here or what, man?"

"Tell you what, why don't you think real hard and tell us yourself, I'm sure it'll come to you."

"I got no idea what you're talking about."

""No? Well let me refresh your memory then, couple of nights ago there was an alley, this guy walked past and you pulled him in and shot him four times in the chest, is it starting to come back to you now, scumbag?" Miles looked away, suddenly very nervous.

"I had nothing to do with that."

"No? Then why don't you explain to us how we found the gun that killed him dumped a few blocks away with your finger prints on it? Huh?" Reagan was looming over the perp, perched on the table to the side of him, Jackie decided it was time for good cop.

"Look Miles, with the convictions you've already got, and the evidence we have against you, no jury on earth is gonna let you walk. Give yourself a chance, give us the guy who paid you for the hit. We'll talk to the DA, see what we can get done for you." Miles put his head in his hands, sweat beading on his forehead.

"Alright, alright, get one off your lawyers down here. And I want my lawyer."

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"So I heard you got your guy." Frank and Danny were having a drink in the wing-backs at his Dad's house.

"Yeah, yeah we got lucky." Frank turned to his son, eyebrows raised. If he thought there was something wrong before, he was sure of it now.

"Alright, what's going on son?"

"Whaddya mean, Dad? Nothing's going on."

"Danny, in all the time you have been on the job I have never once heard you write a collar off to luck. You don't rely on luck for anything. So tell me, what's going on?"

"Aw jeez Dad." Danny sat forward, mulling it all over. "Yesterday morning we had nothing. No witnesses, no history on the bullets from the vic, no surveillance video. Nothing. And then just as I'm thinking that this case is going cold faster than a deep freeze I get a letter handed to me at my desk."

"And?" Instead of replying Danny pulled it out of his jacket pocket and handed it to his father. After giving him a few moments to read it Danny continued. "No prints apart from me, Jackie, and the mail clerk. No DNA, no trace evidence. Typed and printed using generic brand equipment available all over the country. It wasn't posted, apparently it just somehow ended up in with the mail when it came to being sorted. I asked the shooter if he'd told anyone about what he'd done with the gun, he looked at me like I was crazy."

"So you got nothing." Danny sat back in his chair, hand on his forehead. "You didn't report it?" Danny shook his head silently. "Why not?"

""I didn't know if it would affect whether the evidence would be admissible or not. Thought it would look like we'd faked it, planted the evidence. We couldn't have done, no one on this case would frame some random guy just to get a collar. But would a judge believe us? Anonymous tips don't exactly hold up well in court. So I didn't act on it directly, I just ordered a second search and made sure they were extra thorough in certain areas. Everything was done to procedure, it'll all stand up in court, and the guy confessed to it, gave us evidence of cash payments between him and Brooks."

"Still, you withheld evidence in a murder inquiry from your senior officers."

"Weak evidence, it just gave us a hint, that's all, we built the case ourselves. Come on Dad, can you honestly say you would have done it any different?" Frank didn't answer but the cock of his head to the side and slight eyebrow raise said everything there needed to be said. "What I'm worried about is someone somehow had access to not only our case, but knew things about it even we didn't know."

""And they were careful to give you just enough information to send you down the right path."

"So everything would be admissible, right. If they care about getting a conviction do you think it could be someone from the DA's office? Trying to push the case forward?"

"Who not only knew where the perp dumped the weapon, but who he was and his travel plans? I can't see it, they're lawyers, not investigators."

"Well it can't be on our end, there's only me, Jackie and Gormley who know anything about the case."

"So then, who is it?" Both men pondered the question silently. After a while, Danny necked the rest of his drink.

"I dunno, maybe I got a guardian angel, eh? I gotta get home, if this mysterious guardian reappears we can deal with it then. Night Pop."

"Night, son." Frank stayed sat up long after Danny left, a frown on his lips.

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Days passed without anything out of the ordinary occurring in the Reagan family, they worked, they argued, they made up. Kate was nowhere to be found. Finally, on Saturday morning Frank came down early, still in his dressing gown, to find the kitchen table already occupied. Kate was reading the newspaper, a glass of orange juice in front of her that had barely been touched.

"Morning Frank." Barely missing a beat, Frank headed to the coffee pot.

"Frank? What happened to gramps? Or Commish? Thanks for making coffee."

"I guess I'm not feeling facetious today."

"Oh? And what are you feeling today?" He headed to the fridge as he spoke, and started pulling breakfast items out.

"That it's amazing the difference a four-piece suit makes to a man. You're almost intimidating behind that desk." Frank laughed, his mind flashing back to the first time they met.

Frank set his things down, dismissing Baker once she was done with her morning report. He had just sat down at his desk when he jumped at the click of the door to his right. No one was supposed to be in the meeting room. The door swung open, Frank was reaching for his weapon when in walked . . . A girl. A teenage girl, in a soft grey sweater and a beanie hat. Frank froze, she was the last thing he expected.

"Morning, commish." the girl said with a smirk, as she came to stand in front of his desk. Frank tried to recover his composure as his hand dropped from his weapon.

"I wasn't aware I had a meeting scheduled."

"Neither was your PA." her eyes were bright with humour, she was enjoying having him on his back foot.

"Well, you have me at a disadvantage Miss, you know who I am, and why I'm here, but I know neither about you."

"Have you decided not to shoot me?" She asked the question nonchalantly, turning as she spoke to glance around the room. Frank cleared his throat.

"I apologise about that, a job like this makes enemies, can't be too careful. I would like to know how you got in here without any of my staff being aware of it though." She just turned back to smile at him, clearly amused. The silence between them stretched out for a few seconds, Frank felt like he was being X-rayed by her gaze. "You haven't answered my questions, young lady." Irritation began to creep into his voice.

"You haven't asked me any yet." She went to the window and gazed out at the view. She didn't seem the slightest bit interested when Frank came to stand about a foot behind her.

"Fine. Who are you, and why are you here?" She turned to face him, looked him straight in the eyes, and spoke.

"You can call me Kate, and I'm here because I'm your granddaughter."

"Oh really? Flannel doesn't have the same effect?" Kate smiled but didn't reply. "I'll make breakfast, how do you like your eggs?"

"However they come. You've been waiting for me to show up again."

"Scrambled it is. And of course I have." The atmosphere that surrounded them whilst Frank cooked was less tense than it had been so far when Kate had been around. They ate and Kate thanked him for her food, and then they washed and dried the dishes. It was a nice, ordinary moment. Kate didn't let her guard down, but she was as relaxed as he had yet seen her. He was sorry to have to break this up.

"Say what's on your mind, Frank. I know you've been waiting to talk to me." it was unnerving, how adult she sounded.

"Can't get anything past you, I see. Come and sit down." He poured them each a coffee and motioned to the kitchen table. "I think the best thing to do is to be honest here, Kate. Danny had a case this week, one that he didn't have a good chance of solving, and then someone decided to help him. He solved the case, but he couldn't have done it if that person hadn't intervened. Was that person you?" Kate didn't react to the question at all. She just kept looking coolly into his eyes.

"You ran my DNA three times." It wasn't an accusation, merely a statement.

"Yes, but Kate-"

"And you've had me followed several times."

"Yes," Frank said slowly, "And you've always lost them. That's partly why I'm asking you this now."

"You don't trust me." Again, her voice was casual. Frank sighed and dropped his head for a moment before meeting her eyes again.

"Kate, you clearly know a lot more than you've told us. You managed to find us when we didn't even know you were missing. One day you're going to have to give us answers to the questions we have about you and your parents, about my son and how we never knew he'd fathered you. For now though, I want to know if you're hiding something from us about your involvement in your Uncle Danny's case." After a moment Kate stood, anticipating her next move, Frank reached across the table for her hand, but she pulled away, flinching involuntarily. He withdrew his hand, but left it on the table. "Don't leave, talk to me Kate." His words did nothing to stop her from walking to the door and slinging on her backpack, a cold breeze blew in when she opened the door.

"Just so you know Frank, you're right not to trust me. I'm always hiding something." The door swung shut behind her.

Hope you enjoyed it! Please leave a review :)