Kate's visitors disappeared from view a couple of minutes ago, but she can't stop watching. She's still holding the phone when it rings.

"Where are you?" she blurts out, and winces. Way to sound calm, Kate.

"My cab is coming over on 86th, we're close. Everything okay, Beckett? You sound...off."

"I'm fine. I can be over to 86th and 5th in under five." Terse, too. She'll apologize later. She's already slinging the bag over her shoulder.

"Ooookay, we'll run the meter." Castle's voice is muffled as he relays it to the cab driver.

"No, wait Castle." There's zero chance she can hold this all the way through dinner. And no way she's going to tell him when they're not alone. "Uh, can you meet me on the trail? We need to talk." That sounds awful. "It's not bad, I just need to show you something."

"Freaking me out, here." More muffled instructions to the cabbie.

"I know, I don't mean to. I'm fine, Boo is fine, I promise. I just don't want an audience for this."

He groans. "I'm gonna throw up in Amir's cab, Beckett."

She grits her teeth. Sometimes he's such a drama queen. "Castle, I met someone in the park today, and I want to take a walk, and tell you about it. Can you do that? Take a walk with me?"

"Sure, yeah, okay. We're here. See you in a minute?"

"I'm the other side of the playground, I can almost see the street." She ends the call and slows her pace. They're going to have to backtrack to the trail anyway.

In under a minute, he passes through a line of trees up ahead. He doesn't want to flat-out run and look panicked, but he's impatient for her, and doing a half jog, half walk, pulling off his tie as he goes. It's jerky and awkward looking, and she's laughing at him when he finally gets to her.

"Not cool, Beckett, he whines, pulling her into himself. "Not at all."

Beckett smiles into her husband's kiss; it tastes like coffee and cinnamon Certs. "Longest day ever?"

Castle holds her at arm's length for inspection. He's handsy when he's nervous, skims her from shoulders to finger tips and back again, across her back, down and around to frame her belly. "It got a lot longer about three minutes ago."

"Rick, do I look like there's anything wrong with me?"

"Well, no, but...you just sounded all wrong, and with the baby, and honestly, the park is half full of weirdos, and-"

Kate silences him with another kiss. Forget the trail, the lawn around them is surprisingly empty of other people. She has to do this, now.

"Castle, you know in a story when one person tells the other person, 'There's no good way to tell you this?'"

"Heaven help me, Kate, if you're fine and the baby's fine, then whaaat?" he exhales on a groan.

Kate is wearing flats, and she gently pulls him down to eye level by his ears."Rick, I...I think I just met your father."

A beat. Two. His mouth falls open, but there's no sound.

Flummoxed? Befuddled. No - gob smacked. Yes, she thinks, especially the smacked part. She's a thesaurus of confusion; under other circumstances she's sure he would delight in the word choices bubbling up in her – wait –

"Rick, breathe."

He gasps. "What?"

Beckett frames his face with her hands and dives in. "He walked up while I was reading, and sat down and struck up a conversation, easy as you please, about his bad knee and my belly and missing his family, and he gave me this." She yanks the envelope out of her bag and holds it between them with a trembling hand and a skeptical eye, like it would be smartest to throw it and duck for cover. "He told me about Martin Danberg and Sophia. He knows that Alexis is getting out of Columbia early. He has your build and your eyes, and, oh, Rick, he has your hands. He has your hands."

"What?" The magnitude of this has reduced her wordsmith to single syllables. She'd like to tease him, break the tension, but...not now, later. Much later. Maybe never.

"And there was another man, younger, dressed as a jogger. Charles said that the younger man took out Stephen Winter. A hit, Castle, a covert assassination, directed by your father. He really is a spook."

"Charles," he breathes out. "His name is Charles?"

"Yes, or that's what he told me, at any rate." She has no idea at what point they ended up in the grass, but they're both kneeling on the lawn, and she's almost in his lap with the letter crumpled between them. She settles back a little and he smooths the envelope out against her thigh. Castle is too calm, maybe. Or just too shocked to do anything else but keep breathing, until...

"But you're okay, right? Kate? I mean, nobody touched you?"

Kate blinks. Oh. "He uh... kissed my hand? Odd that I allowed it, but I wasn't really playing my A game."

A nod. "Okay." Castle turns the letter over in his hands, traces a thumb over his printed name. "Okay." He slips the letter in his coat pocket, the same pocket Charles kept it in, she notes, and he takes Kate's hands, drawing them both to their feet.

"Home?" he asks, with an apology in his eyes. "I don't think I can do Mariano's tonight."

"Yeah, sure."

He's calling Wan Two's with their usual order as they head toward the street to hail a cab. It's rush hour. The food will get to the loft before they do.

He doesn't let go of her hand, even to climb in the back seat. He buckles her in like she's a little kid, but his wife has the presence of mind to bite back her natural impulse to gripe. He crowds her from the middle of the seat and turns a face into her hair, laying a heavy hand on her swollen belly as their driver pulls out info traffic.

Forget the longest day ever - it's the quietest cab ride ever.