Fill in for "Driven." A conversation between Beckett and Alexis.

The lines of text blur, and she pauses to rub her eyes, feeling a sharp twinge through her temples. She looks at the words again: the CSU report from the car crash site. She's been over it a dozen times but there's always the chance that she'll see something she missed earlier. If there is a straw, I'm grasping, he says in her memory and the words blur again, not from eyestrain this time.

After a moment she's able to read again, and it's some time later that she realizes she's reading the same paragraph over and over again, to the point that simple words like inch look like nonsense. She should—

"Kate?"

Alexis is standing in front of her desk, posture straight and hands clasped in front of her. There's something peculiarly formal about her appearance, and her voice is carefully measured as well when she asks, "Is this a bad time? I need to talk with you."

It takes Beckett a moment to find her words. She's used to speaking in cop-talk and honing the desperation from her voice in her fruitless inquiries; it doesn't help that the last time she spoke to Alexis beyond simple statements like Nothing yet and I'll keep you updated was when she went to the loft and asked Alexis and her grandmother if they'd noticed any odd behavior from Castle. "Of course. Are things…" She almost said Are things all right at home, and of course they aren't. "We can go to the break room and talk if you like."

"Here is fine, it that's OK," Alexis says, taking a seat in the chair. His chair. She sits and regards Beckett for a moment before speaking.

It isn't often that Beckett sees much physical resemblance between Castle and his daughter. Their similarities are matters of personality and speech. But they have the same eyes, that remarkable blue that usually looks as warm and pleasant as a tropical bay. But that blue can turn chilly. No one knows that better than Beckett, who remembers all too well the rare occasions when Castle's eyes were nearly glacial in their coldness.

Alexis's eyes aren't that cold. At least not yet.

"It's been bothering me, what you said the other day." Alexis pauses. "I've been trying to see it from your perspective. I know that you have to follow up on all the leads and evidence. Gram told me to remember that you see the worst side of people every day. That you always hear people say that so-and-so couldn't possibly have done that terrible thing. But this is Dad. I have a hard time understanding how you could doubt him."

Beckett's been expecting this, but expectation hasn't helped her come up with an answer. "I know how much he loves you and our grandmother. I don't see any way he would ever leave you."

Alexis frowns. "I don't…do you think he'd leave you?"

Ah, there's the crux of it, in six simple words. Do you think he'd leave you? And the answer comes down to what she knows and what she feels. What she knows: That he wouldn't, because he loves her. What she feels: That he would, because that's what the people she cares for do. Leave. They're lost to hit men or to bottles of liquor, they leave for nicer jobs or doing good works or lives that skirt the wrong side of the law. She once teased Castle about being the common denominator in his failed marriages, but her track record is far worse: parents, lovers, friends, mentors. And when she saw that security cam footage of Castle dropping the money into the dumpster, an interior voice said Add fiancé to the list.

"Kate?"

Alexis is looking at her strangely. Has she voiced any of her thoughts? She's so exhausted mentally and emotionally that it's hard to be sure. She's exhausted physically as well—the only sleep she's managed in the last couple days is the occasional quick catnap on the break room sofa. She hasn't wanted to sleep longer than that, afraid she'll miss some new break in the case, afraid of the dreams that plague these naps, dreams of terrible screams and the smell of burning flesh.

"I can't remember seeing him as happy as he was these last few days, because he knew that you'd be married soon. He couldn't have fooled both Gram and me all that time. Between the two of us, we can always catch him in a lie." For the first time, a smile graces Alexis's face. "He was making us both crazy singing that 'I'm getting married in the morning' song from My Fair Lady. I told him if he didn't stop I was going to get earplugs in your wedding colors for all the guests and…" The girl's smile breaks suddenly, like glass, and tears well up in her eyes. "Right now I'd give anything to hear him sing again."

"So would I," Beckett says, though the ache in her throat makes speech difficult. "Alexis, I want you to know…" She's not sure what to say next. How can she explain that deep down, it's not him she doubts, but herself. Whether she's worthy of the steadfast, almost ferocious love that Castle's capable of. Whether her doubts, no matter how fleeting, make her unworthy. And how can she explain that at times it's easier to think that he might have left of his own accord than to wonder if he's dead or imprisoned or undergoing some sort of torture.

Before she can find the words, Alexis speaks again: "He doesn't let people in easily. It looks like he does; he has a lot of people he knows, people he's friendly with, but he doesn't let many people in to see the real him. If you're one of those people…and you are, Kate, don't ever believe you aren't…he'll do anything for you and never leave you."

She can't find the words, so she stands and holds out her arms to Alexis. But the embrace never comes, because the world grays out for a while.

She's lying on her back, looking up into blue eyes. But there's no dazzling blue sky, no grass beneath her. She's on the sofa in the break room. Instead of the smells of blood and adrenaline there's the mingled scent of old coffee and burnt microwave popcorn. It's Alexis looking down at her; behind the girl, also looking worried, are Ryan and Esposito. Beckett distantly notes that worry makes Ryan look younger and Esposito look older; it strikes her as the sort of observation Castle would make.

"What happened?" she asks.

"You fainted when you stood up," Alexis says, looking at Beckett closely. "Maybe you should get some rest."

"Should probably get some food, too," says Ryan.

"I'm fine," Beckett replies, though as she says it her empty stomach roils with acid.

"Bullshit," says Esposito. "You've been living off coffee and trail mix."

The click of heels on the break room floor, and Captain Gates enters. "Miss Castle, may I speak with you for a moment?" she asks in a kinder-than-usual voice.

"I'll be right back," Alexis says and leaves the room with Gates.

"Why don't you go home for a bit?" Ryan asks as Beckett shakily sits up on the lumpy sofa.

"I don't want to miss anything." She knows it's irrational, but she can't shake the feeling that if she lets her guard down for more than the absolute minimum, she'll miss something—some lead, a new breakthrough—that will make all the difference.

"We'll keep you in the loop. We promise," Espo says.

"I need a word with Detective Beckett," says Gates, who's come back into the break room. After the boys leave, glancing back over their shoulders, Gates sits down next to Beckett.

"I know how much this means to you," the captain says. "And I've held back these last couple days. But you need to get some rest, Detective. Running yourself into the ground won't help you or Mr. Castle. So go home, and don't come back until tomorrow."

"Sir, I–"

"That's an order, Detective. I've already arranged a cab to take you and Miss Castle home, and I've asked her to make sure that you get a good meal in you and some decent rest." Gates pauses, and then says, "They're not just his family, they're yours. You all need each other now."

She's about to protest that she's fine, and then remembers the way the words on the CSU report blurred and became nonsensical, the way she read and re-read not because it would do any good but because she would be doing something. Like avoiding Alexis and Martha, afraid they'd shun her for her doubts and for her failure to bring Castle home safe. "Yes, sir," she says.

"Until tomorrow, Detective. Take care."

The cab ride is a silent one for the first few minutes, Alexis staring out the window. Without taking her gaze from the passing city, she says, "The waiting is the worst part. It reminds me of…"

"Of what?"

"Of Paris. After Sara and I were separated, and it was just me in that cage…they didn't mistreat me, but that didn't mean they weren't going to, and I was just…waiting." She pauses, takes a deep breath. "What kept me going was knowing that Dad would do everything he could to get me home. I knew it might not happen, but I never believed he wouldn't try. That's what I hold on to now. If he's not…if he can get home to us, he will."

There's faith in the girl's voice and expression, absolute and unshakeable. Beckett's own faith is not as rock-solid, but when she gets to the loft and lets Martha feed her (a hearty soup that brings her ignored hunger to life, and of which she eats three helpings) and settles in to rest on the couch (she can't face the bed, not yet, it's too big without him), her guilt for her imperfect faith recedes. If Alexis and Martha can forgive her doubts, then maybe Castle can if (no, when) they find him. And maybe one day she'll forgive herself.

Hope you enjoyed it!