Chapter 1

It was just lying there. Small, black, almost invisible on the corner table.

Richard Castle, author, almost famous – his books were selling in their millions, but so far his face wasn't instantly recognisable to the interested bystander on the street – had taken the table, perfectly placed to observe the world passing by while eating a hurried lunch, and only after he'd sat down had he noticed the small black book. He hadn't really noticed the previous occupant: just a flick of dark spiky hair on a tall woman, on her phone, talking urgently but too low for him to hear anything, not that he'd ever considered he'd need to listen to her, then dashing out into the bright April day.

The book was just lying there – not a book, a diary. Surely she'd dash back to collect it? He ordered his lunch, ate it, looking at the diary every minute or so and forcibly not opening it, but as he drank a final coffee, she still hadn't returned; and the diary was still lying there.

He should hand it in to the staff. He had no reason at all to think that they weren't reliable, so they'd be sure to give it back to its owner, who'd be sure to return here for it.

And yet…he could find her, and give it back. It would be fun – a mystery of his very own to solve, where he didn't know the ending. Curiosity, his besetting sin, was nibbling at his neurons, nagging him to play this game. Whoever she was, she might be…well, she'd been tall, and now he thought about it, slender, and if she was pretty too, then, well, who knew where it might lead?

He wouldn't start it now, he decided, though his fingers itched and burned to open it. He'd take it home, and look in private. He paid the check, slipped the diary into his pocket, and hastened home.

Home, though, was a ferment of high emotion and higher voices, and in the confusion, hubbub and outright hysteria caused by a broken string on his daughter's violin, he forgot about the diary.

String fixed – temporarily, at least until Alexis's violin teacher could do it properly – Castle slid between his sheets in his – still quite new – beautiful, now-I-can-live-the-way-I-wanted-to, loft, and settled down to sleep, eyes drifting closed, perfectly peaceful –

The diary! He jerked into full wakefulness, and grabbed a robe to search it out: finding it in the pocket of his sport coat, and took it back to bed with him. He'd just look to see if it had a name, or better yet an address or phone number.

There wasn't. Well…that just made it more of a fun challenge. In the morning, he'd start to investigate, just like a PI would. It was going to be fun. Picking up all the clues from the diary and finding its owner, who would be happy to have it returned.

He fell asleep smiling.

In the morning, after breakfast, he had some qualms. Diaries were, in general, private. It felt a touch intrusive, to be reading a stranger's diary. But then again, he self-justified, she was a stranger – and anyway it might not even have been hers. It could be anyone's diary: he'd thought that she'd been at his table, but honestly, he wasn't sure.

Eventually, curiosity defeated conscience, and, accompanied by another coffee, he sat at his desk, pen and paper (for notes and clues) at hand.

He opened the diary. Then he closed it. Surely if he was going to imitate a PI, he should examine the physical attributes of the diary first, for clues. He briefly regretted that he had neither an insufflator nor fingerprint powder – and anyway, he had no access to a fingerprint database if he did.

Or…did he? He could always try to persuade Roy. It wasn't likely to work, but it was worth a go. Maybe there'd be some newbie on Roy's team – hadn't he said he'd picked up a brand new detective, a real hot-shot? Maybe he'd help. Roy's face had indicated that he might be a hot-shot, but there was something wrong – causing Roy a bit of a problem, Castle had intuited. Maybe it wasn't such a long shot after all.

Anyway, he thought to himself, back to the diary. He thought for a moment, and then wandered upstairs to raid Alexis's bathroom for talcum powder, then thought again and went back down to the kitchen for flour. Less likely to cause domestic disharmony, flour – and easier to replace.

Before dousing it in flour, he inspected the cover carefully. Plain black, with a slight texture. No brand name, which was deeply disappointing. As he'd already discovered, no name inside. He put the diary back on his desk and tapped out a little flour over it, shook it gently, and looked at the now-revealed prints. Some, of course, would be his. That would be easy for Roy's hot-shot to exclude. He bounced a little at the thought of being fingerprinted, without also being dressed down for some minor misdemeanour (or borrowing a police horse). He took precise photos with his phone, ensuring that all the detail was in sharp focus, and then saved them down.

Finally, he opened the first page, and began to read.

Dear Diary. What a cliché. Doesn't matter, though. Nothing matters now.

The ink trailed off. Castle squinted at the page, detecting a slight deformation, as if the page had been wet, then dried – as if its owner had been weeping when they wrote it. Already, he didn't like the tone of the entry.

You can't think like that! he thought at the entry. Of course something must matter. But the rest of the page was blank.

Chilled, he made himself another hot coffee, clasping his hands around the mug, searching for warmth. He really didn't like the tone of the entry. It sounded…defeated. Hopeless. He wanted to tell the writer that life wasn't like that. It was good – there was always hope, always a reason for joy. Now, he didn't believe this diary belonged to the woman he'd seen – she'd been focused: speaking and moving with purpose and passion. She hadn't been hopeless or defeated. Any last little tinge of guilt that he should have handed the book in to the café staff slipped away. He had to find this person: had to change their view.

Of course, maybe that was just one bad day. He turned the page.

Dear Diary. Still a cliché. Who cares? I don't. Dad's drunk again. I picked him up from the tank, again. He didn't know me. I should stop. He doesn't care. There were more of the slight indentations, a touch of mottling, a tiny smudge on the writing.

Castle made a note. Alcoholic father. His first clue. Not exactly determinative, but it was a start. You can't cure it, he thought, born of knowledge of early friends, who'd dropped away, dropped out, and in some cases dropped dead. He couldn't help them, and they wouldn't help themselves, but it had taken him time to learn that their decision wasn't his choice or his fault.

But it wasn't quite as bad as the previous entry. I should stop. That implied that they weren't going to stop, and, he theorised, that family mattered to them. A note of hope, maybe? At least not such unrelenting gloom. He turned another page, and then a few more, all blank.

Dear Diary. Today I made detective. Finally reached my goal. I'll be able to investigate, and finally get some answers. Maybe then Dad'll stop drinking.

Castle smiled. Hope burned through every word: even the handwriting was, somehow, happier. He made another note – Detective – he checked the diary date – on February 25. Now that was a much more tangible clue. There couldn't be that many – could there? Roy would tell him, anyway. Roy was happy to answer his questions, and Castle needn't even tell him that this wasn't book research.

But what did the writer want to investigate, or get answers to? Detective covered a multitude of crimes – Robbery, or Narcotics, or even Homicide – oooohhhhh, if it was Homicide that would be –

Not amazing. Horrible. Because the only possible explanation for get some answers in that situation was that someone close to the writer had been murdered, and that was definitely not a subject for his usual enthusiasm. (A small portion of his writing brain said but it would be great to meet them and hear all about their work. He squished it.)

Somehow, it had gotten to be lunchtime. This PI-pretence was fun, Castle thought, pushing away the idea that his missing modern-day Pepys had suffered tragedy, and he'd even found two clues. He made himself some lunch, and took it back to his study and the diary, making sure he didn't drop anything on the book.

He flipped past several blank pages, then more, then more. Two months, more or less, of nothing, which was irritating. He wanted progress. Clues. Immediate answers.

This wasn't one of his books. He didn't have the answers, and he didn't like it. He was so used to having the answer in the back of his head – or on his outline – that he'd forgotten what it felt like not to solve a mystery. The solution, of course, was just the same as it had been when he was a child – read on.

Only a couple of weeks ago, there was a bleak entry.

Dear Diary. I'm so tired. There's so much to learn as a detective, and I'm still bailing Dad out. I told him last night was the last time, and I really meant it. I keep going back to the file but I can't see anything more. I'm missing something, I know I am. But I'm so tired and I just can't do it tonight. I can't lose my job, I worked so hard to get it. I have to sleep, but then I'll dream. I hate the nightmares. I wish… I wish I never had to go to sleep again, never dreamed.

I can't save Dad. What good am I if I can't save Dad? He'll die if he doesn't stop drinking. If he does…what's the point? I might as well be dead too.

A chill ran down Castle's spine. He frantically turned pages to the next entry, a week later.

Dear Diary. I'm fucked. M caught me in the Archives. He said if I look at Mom's murder –

Oh, fuck. Their mother? The writer's mother had been murdered? Oh, fuck.

- again, he'll bench me. I can't bear to be benched. He was so disappointed. I could have dealt with anger. But now I'll never find out.

I might as well be dead. Dad's drunk, and now he hates me because I told him I wouldn't go get him. Mom's dead, and I can't find her killer. Even on the job, now I've got a black mark, card marked. I might as well die.

I've got no reason to live. No-one would miss me. Dad wouldn't even notice I was gone.

Castle stopped reading. He had to find this person. He had to. They were on the fast track to talking themselves into suicide. He took a glance at his watch, and found it was mid-afternoon. Roy should be around.

"Hey, Roy."

"Rick? Why're you calling me?"

"Thought you might want a drink this evening, and a chance to win back what you lost last week."

"And?" Roy asked.

"And I've got some questions for you."

"Thought so." Roy sighed. "Okay. But I want the good whiskey."

"Sure," Castle said expansively, momentarily cheerful.

It wasn't till he cut the call that his worry returned. Okay, he'd pulled Roy in, but urgency grabbed at his guts. Whoever his diarist was, they were in deep shit. He had to find them.

Save them, whoever they were.

If he could.

He slumped, and then forced himself to re-read every entry, searching for clues, hints, anything that would lead him to the writer. Convince them there were reasons to live. There were always reasons to live. Even in the darkest days, there was – there had to be – a possibility for joy. Otherwise, what was the point? But this diarist had lost all hope. No family, no mention of friends, or colleagues, except for a boss known only as M. If, though, they were a detective, then M could be their boss – must be, to be able to bench them. So that meant – oh. Any sergeant, or lieutenant, or captain, or higher. Not a small cohort to search through, but maybe Roy had access…

So. He knew the date they made detective, that their dad was an alcoholic, that their mother was murdered, and that they had some sort of a boss or superior with the initial M. And he probably had their fingerprints. He'd better ask Roy if the NYPD had a database of its police detectives' fingerprints. He wrote down everything he wanted to ask, and left the list in a drawer, with the diary, for later, swapping it out for the pack of cards.

Roy arrived shortly after dinner, bestowed an uncle-style hug on Alexis and was then ushered into Castle's study before Alexis could ask overly-intrusive or embarrassing questions, though she would have had an excuse, being only just ten.

"Whiskey?" Castle asked, already reaching for the bottle.

"Sure. I guess I'll be paying for it one way or another, in dollars or in information." Roy grinned. "So which is it going to be?"

"Information."

"Oh? I thought Storm was a PI, not a police officer?" Castle squirmed a little. "Rick? What aren't you telling me this time?" Roy glared at him, and Castle squirmed a lot more.

"Uh…I found this diary, and I wanna get it back to its owner."

"And?" Roy waited.

"Whoever it is," Castle squeezed out of his closing throat, "they've got real problems. It sounds like they're right on the edge."

"So? You're not normally too bothered about playing the rescuer. What makes this one different?"

"I…I wanna know their story," Castle realised. "I gotta give it a better ending."

Roy raised eyebrows at him. "So it's just another story?"

"No! But…I can't just let them drown without at least letting them know they've been heard."

Roy clapped slowly. "Well, well. Chest-signing celebrity Castle has a conscience. Better not tell your publisher, she'll excise it with a blunt pair of scissors. Nice to know you're not just a playboy." He grinned. "Not that I mind you being a rich playboy when I'm rooking you at Texas Hold 'Em."

"I've won every game!" Castle squawked. "You and Judge Markaway have more tells than William had apples."

Roy laughed. "Gotcha. Now, what do you know about this person – and don't try to tell me you didn't read the whole diary, 'cause I won't believe you on principle. You're as nosey as all get-out and the last time you met a scruple you probably deep-fried it and ate it."

"No, it's a very tiny apothecary's measure," Castle said absently.

"I don't wanna know about something from the Dark Ages. What about this suicidal" – Castle jerked, and his mouth pinched – "diarist?"

"I know they're a cop – a detective."

Roy came to attention. "Okay, now I'm in. I don't want any cops running around when they're not up to it. Too much chance of them going off the rails or over the edge." Thought skated across his face, and his lips tightened.

Castle noticed. "What's up?"

"No… nothing. Just a thought, but it's not for now." He shook his head. "What else? Detective doesn't exactly give us much to go on."

"They only made detective on February 25 this year."

"That would be the last round. That narrows it down a bit, but there are still a lot of options. That it?"

"No." Castle gathered himself, and stared at the table. "Uh…whoever it is, their dad's an alcoholic and their mom was murdered." When he looked back up, Roy's face was worried. "And likely I've got their fingerprints."

"How?" If Castle hadn't looked down again, he'd have seen the fast calculations running through Roy's face, and his absolute terror of the answer.

"Uh…I floured the cover, real lightly, and took photos. I mean, some are mine, obviously, but do you maybe have prints from the detectives?"

"Nope."

"Oh." Castle's face fell.

"Still looking for the easy option, Rick?"

"I just wanna help. Even if I only get them their diary back, it'll show them that good things happen too."

"And what did you want me to do?"

"Well," Castle wriggled and hitched, "um…you said you had that new detective, your hotshot who made it faster than anyone ever, and I thought maybe if he wasn't too busy" –

"She."

"She? Okay, if she wasn't too busy, she could maybe help me find whoever this is…"

"So lemme get this straight. You want me to let you work with my newest detective, who should be working on cases, on this data matching chase, because you've got a bug up your ass that they're going off the edge."

"Uh, yes?"

"Uh, no."

"But" –

"Wait one second till I'm done. No, you can't do it in working time. But, you can come and meet her and see if she'll help you off the clock. I'll approve her using the databases."

Castle pouted at him. "That the best you can do?"

"Yep, and that's pushing the envelope."

Deep in his manipulative brain, Roy prayed that Castle would take the bait – he didn't usually back down from a challenge. Roy could tell him that he knew exactly who the diary belonged to – but he wasn't going to, because he was terrified that his new hotshot was about to do something…permanent. He, Roy, needed a better solution than simply giving her back her diary, and it looked like it was sitting right in front of him, nervously shuffling a pack of cards.

"We'll need to be a little cute about it, though. In fact, it's more of a training exercise," Roy said, and smiled evilly. "We'll tell her that you're researching for a book, and you want to know how to track down a diary."

"I guess," Castle said doubtfully. "But shouldn't we find this guy as fast as we can?"

"Ah, well. That's the cute bit. I'll use all of your information to find them, and make sure they're okay. It shouldn't take me too long. And I'll get a chance to see how my newest detective does with hardly any information, step by step. Let's start with just the fingerprints, hmm?"

"Well" –

"I can insist they go to a shrink, or bench them, or take a whole lot of action that you can't. Think, Rick! I know it's hard for you to see past your enthusiasm, but how's someone gonna react to you turning up and saying Hey, I found your diary and I wanna save you, huh? If they don't shoot you, they'll have you committed, or arrested. I don't guess you want to be bailed out by your mom again, do you?"

"Not in front of my daughter."

"Mm." Roy nodded. "Now, how about I fleece you at poker for a while, and I'll have some of that whiskey you're hiding too."

Thank you to all readers and reviewers.

This came from a prompt whose suggestor I forgot to write down: Beckett loses a diary full of reasons to die. If you would like to reveal yourself, I'll credit you for the inspiration.

Posting, as usual, Tue/Thu/Sun. 25 chapters, for those of you who'd ask. Rating may change up to M later on.