A/N: So nervous and excited for this chapter, I think I almost delayed it on purpose while I tweaked it and tweaked it because it's such a big deal for the story . . .


Chapter Twenty Four: And you watch me fight my own insanity.


Chapter twenty two of 'Heat Lost' is the one that ultimately provides the break in the case for both Kate and also for her fictional alter-ego, and although it doesn't hit her until much later on, 'twenty-two' is of course an 'odd sock' all of its own – its the number of novels Richard Castle had written before he met her.


It's late in the day when the break comes; Kate has reached the final four chapters of 'Heat Lost' and she's beginning to wonder where the crucial information is going be. Nikki and Roach are stymied on another investigation. Several days into investigating Detective Nathan Butcher's murder and to Nikki's everlasting frustration, they are firmly up against yet another brick wall.

Nikki's unsolved body count is now sitting at five, and on the more personal side of the novel - Jameson Rook is still very much missing while Nikki is daily growing more frantic about his safety. Kate can completely relate, but as the 'reader' of the book she's aware of what Nikki isn't - that Rook is actually safe and that he's doing okay. He's just cut off and he's incommunicado, but he's doing his damnedest to get back both to civilization and to her. In her heart Kate can't help but hope that the story has been written this way because Castle's telling her this is also exactly what he's trying to do here.

With nothing but dead leads and empty spaces in her suspect column, all Nikki's got to work with in her latest investigation is a cryptic piece of paper that Dr. Lauren Parry pulled out of one of Detective Butcher's shoes during his autopsy. Kate reads past this point at first. She doesn't see the message Castle's left for her in it, until two chapters later into the novel when Nikki finally uncovers the meaning behind the mystery piece of paper as it relates to her investigation. And then Kate kicks herself hard mentally, for not seeing already what this piece of information really is.

'Under the Gun'.

It hits her so suddenly, like a blinding flash of inspiration. God she's an idiot.

After all she remembers that insane case so very vividly, and every single one of its painful repercussions.

And maybe, she thinks, that's exactly why it wasn't so obvious to her on her first read through. Anything that might lead her to thoughts of Mike Royce is still somewhat untouchable by her conscious mind; deemed simply too painful. So Kate doesn't often allow herself to go there. However, that case certainly involved a cryptic piece of paper of its very own, one that also had a double meaning and was found hidden inside a murder victim's shoe.

Castle knows how hard that case was on her. He wouldn't use it so blatantly here unless he wanted to jar her, and if he's jarring her psyche on purpose then he's clearly trying to get her to pay attention to something.

So Kate goes back two chapters, and then she reads it slowly and more carefully all over again.

For Nikki Heat the cryptic piece of paper from Detective Butcher's shoe is interesting firstly because it was hidden, and second because it has numbers scrawled all over it. The numbers are showcased clearly into groups of three numbers at a time, in defined sets of two, there are twelve unique sets of them in total.

It's a distinct pattern, but nothing about the grouping is immediately obvious - so it's a mystery. Still, dead-ended as they are with all of their current murder cases, Detectives Heat, Raley and Ochoa have nothing else left to go on, so unravelling the meaning behind these strange strings of numbers becomes the soul focus of their combined attention.

It takes Nikki and 'Roach' a lot of time on the internet and a couple of days worth of digging in order for them to figure out the pattern to them. But eventually the three detectives uncover the key, and turn their twelve sets of six numbers into four separate strings of eighteen.

This leads their investigation to four numbered Swiss bank accounts, with one belonging to each of their four initial victims - although the accounts are under different, perhaps 'real' names. Names that Nikki only manages to extract from the overseas bank, because the accounts themselves are accessed purely via 'fingerprint' and her four original homicide victims are each a perfect match to one of the numbered accounts.

The discovery is staggering. Now – clearly, all of their cases are linked and they're no longer dealing with two entirely separate murder investigations. Both the original four and now Detective Butcher's seemingly random 'wrong-place-wrong-time' murder have clearly been orchestrated by the same individual(s). Because how else can the detectives explain Butcher being found dead in possession of secret financial information on each of the other four victims?

Kate can't help it and she can't stop it either, she smiles somewhat sadly as she reads this part of the book again. In her mind she just sees him so clearly, and she sees him smiling too. Sees him looking at her all twinkling eyes, his infectious grin so insufferably smug and he's so heart-breakingly handsome as the words 'Castlesque twist' trip lazily off of his tongue, that want blind-sides her - hard.

She holds onto the thought of his smile, even as the image of it in her minds-eye inevitably fades, and the wave of need is replaced by one of desolate sorrow that sweeps over her sudden and fiercely, leaving her aching and despondent in its wake.

The cop closes her eyes for a moment and breathes shallowly through the nagging pain. She swallows it back, swallows it down, knowing innately that she's sitting on the edge of a discovery here and that Rick's guiding her to it, nudging her gently, leading her back.

Kate opens her eyes with renewed purpose, she's close to answers – she is, and so once more she begins to read.

The newly uncovered bank accounts revert 'to the United States government' upon their owners demise, a condition so strange that it leads Nikki first to the State Department and then finally to the 'Agency'. Her homicide victims are all agents, spies in point of fact, their numbered Swiss accounts in all reality the property of the CIA.

The CIA.

No wonder Nikki's been getting nowhere with her investigation, the lives of the people whose deaths she's been investigating aren't really their lives at all. They're fronts, carefully crafted identities that aren't real with substance and background provided purely to conceal. And now that Nikki has uncovered this the 'Agency' and its full might steps in. The NYPD are instructed firmly to back off – that the deaths of their agents are already being investigated and that they've only permitted Nikki to continue with her investigation up to this point, because they were confident she wouldn't actually break past any of the cover identities.

Now that she has - they demand to know how she did it? Nikki however, still needs to know who killed her fellow cop, she can't let it get buried – so while she agrees to back completely away from CIA's cases, she refuses to reveal to them what lead her there. For now Butcher's mysterious piece of paper remains her secret – for as long as she can keep it - while she and Roach struggle furiously to uncover where he got it from, knowing that it's only a matter of time before they'll ultimately lose control of his case also.

And Butcher's death might not mean much to the CIA – but it's important to the NYPD. It's important to Nikki.

It kinda hits Beckett then, the beauty of what it is that he's done here, how brilliantly clever a writer he's proving to be, and she puts 'Heat Lost' on her desk with shaking hands, grabs for her cell phone and calls Esposito immediately.

Excitement and adrenaline are flowing freely through her – the heady amazing thrill of discovery.

She sees clearly where the message lies now – where Castle has hidden it inside the story. It's the sets of numbers that will tell Kate what she needs to know, she even knows exactly how – and she gets it all simply from the asshole at the CIA who Nikki's been forced into dealing with in. The clue hidden simply inside the character's name. Hidden in plain sight for just Kate to see.

Because this name is an asshole who Kate Beckett once had to deal with, and one who very memorably only ever called her by the name 'Nikki Heat'.

Only Castle.

Scott Dunne.

The name seems so large on the page.

Kate wants to laugh, she can hear Castle's voice from way back then – the comment he once made, as if he was beside her.

'Busted you smug jack-hole'.

She's trembling, certain but . . .

No. She's certain, she is - it's there because it has to be.

Kate can't sit still and she gets up, paces around her desk, wills Esposito to find Ryan quickly and get back here, she could of course begin to find it – but she wants them here, wants to do this with them, its only fitting for them to do this together as a team.

Just then the elevator pings its arrival and to her immense relief as the doors slide open both her partners practically spring into view, her face splits into a smile at the twin looks of anticipation and worry on each of their good-looking faces.

Ryan makes it to her desk first.

"You found it?" he asks.

Beckett nods, her eyes going from Ryan to Esposito, who meets her gaze with a knowing smile.

"I told you," he says softly, "said you could do it. What have you got for us Beckett?"

The brunette detective takes a calming breath to contain her excitement, she paces in front of the murder board that's still barely filled in for Ethan Slaughter, takes a long look at the barrenness of it and it has the desired subduing effect. Kate spins back around, hands twisting together nervously.

"Okay. The second year that Castle was shadowing me we caught a case that the FBI honed in on," she begins.

Esposito nods, remembering. "Yeah I remember that. Wasn't that the case with the nut bar who blew up your old apartment?"

"Yes, exactly." Kate answers. "The serial killer who dedicated his murders to me – or rather, to 'Nikki Heat', he inscribed the bullets he put in his victims with letters. Three victims at first, with the letters spelling out a message to me – 'Nikki will burn.'"

Ryan looks intrigued. "So there's something similar in the book?" he asks.

Beckett shakes her head. "No, not exactly. But the killer's name is there, the one we uncovered finally after plowing through the fake identities."

Her partners stare at her expectantly.

Kate rolls her eyes. "Scott Dunne," she tells them.

Ryan bites his lip. "So Castle's named a character in 'Heat Lost' after this killer we caught – this 'Scott Dunne'?" he questions.

Esposito looks thoughtful. "Clearly Beckett you think that means something."

"It does," she tells them, "in fact it's the key – but there's more before we get to it."

"Alright – go on," he says encouragingly.

"So, in the novel Nikki and 'Roach' have found a link between their five homicides. The murder of Nathan Butcher uncovers a cryptic piece of paper that ties them all together. Now the book has one very specific meaning for this piece of paper – but Castle using the name 'Scott Dunne' is a message to us that there's another one."

Kate's partners both smile, Ryan look almost giddy.

"You know what it is," he says.

Beckett nods. "Yeah, I believe so," she says breathlessly. "I think the key also lies back in the Scott Dunne case, because as well as the bullets, he sent me a second message, a string of numbers on a bloody bandage. Castle was the one who figured out what the numbers meant – they were a reference key for words within the pages of 'Heat Wave'. In this manuscript, the piece of paper that Nathan Butcher had hidden also contains strings of numbers – and I've seen this pattern before – strings of three in sets of two. Regardless of the novel's use for them, I'd bet my badge we can use these numbers the same way we did back then. They're a reference key for this book guys, twelve words if I'm right about it. Twelve words that are a message direct from Castle that will help us to solve this."

Esposito is the first of her partners to speak.

"Well okay, lets do this."

Her partners grab their copies of the manuscript, and together the three of them work their way through it – finding each word in turn. It takes but two words for them all to agree that Beckett's cracked this – 'Be careful'.

They stare triumphantly at each other when they've found all of them, Ryan grins at her like an idiot and Esposito nudges her shoulder in victory.

"You did it," he whispers to her.

"We did it." Kate answers back.

Their discovery sits on the white-board in black sharpie, beneath Slaughter's incomplete murder time-line.

'Be Careful Cesar Valez Murdered Slaughter And He's Watching You Always Castle'

Kate steps close to the white board and stares at the name of her cop-killer, the name of the man who somehow caused Castle's sudden disappearance.

"Alakazam jackass," she says quietly.