"I. . .can't. . .believe. . ."

"Breathe, Castle," she laughs, running a little slower to let him catch up.

"Can't believe you talked me into this," he groans, using an arm to wipe sweat from his forehead. He's wearing those loose basketball shorts and a tshirt that says "Guns don't kill: Dads with pretty daughters do."

"Stop being a baby," she laughs again. Kate nudges him towards the middle path and they take it towards the water. The park in the afternoon light looks dirty and tired, but Kate is energized by the bounce in the pavement, the thrum of blood in her ears, and the uneasy rhythm of Castle breathing next to her.

"I'm gonna die," he pants.

"You are not." Kate measures her breaths to the time of her footsteps. "In fact, you've been working out in secret, haven't you?"

He stutters on a breath and chuckles. "How'd you know?" Sarcasm drips from his voice.

"Okay, so you're not working out in secret. Still, you're in shape. Your act is a little over the top, Castle. We're basically jogging here and you're panting like a dog." Kate nudges his shoulder with hers and increases their pace.

"No fair. Now you're going faster."

"That's what you get for pretending to be incapable."

"Slow up," he whines again, his breath whistling in his chest.

She ignores him, goes a little bit faster now. Not the pace that she set with Alexis, so it's not grueling or anything, and she knows that Castle can do it. "Have you been lifting weights lately?"

"Not really."

She grunts. "Are you telling me that you're just naturally athletic and you've been wasting your potential?"

He huffs a laugh, catching the reference. "I don't know what you're talking about."

"You're the type that every woman hates," she says, measuring her breath between the words to keep in rhythm.

"Don't hate me because I'm beautiful."

She shakes her head with a laugh. Kate risks a glance away from the path to study Castle as he runs beside her. His tshirt already sports sweat stains, and even though she can hear him breathing, he doesn't look strained for air. A natural.

"You were running some before," she presses.

"When I followed the 12th," he admits.

"Why?"

"Because you did a lot of running down of suspects. And I wanted-" Castle sucks in a breath and takes a long stride over a pitted section of the path; Kate skirts around it to the other side. "I wanted to be able to chase after you."

"You certainly did."

"Now look. I chased you down, but. Still running. Somehow, not fair." His words are choppier now that she's subtly increased the pace again.

"Sure it is. If I've got to be social and make nice at a charity event-" Her own breath is shorter as well, so she eases off a bit, and Castle matches her. "If I've got to do that, you've got to run. Sickness and health. All that."

"Also says richer or poorer."

She grunts at that.

"You trying to kill me then? Get outta your contract early?"

Kate lets loose a laugh and veers into him, knocking him off the path a little. Castle yelps and jumps over a dip in the grass, then heads back towards the pavement. She's smirking to herself.

"So you're going to do this run with me. And then what?"

She holds out her hand, as if to guide him back onto the path. Castle ignores it and springs up next to her, practically vaulting over a plastic cup someone has left beside a park bench. Natural athlete. So annoying. He probably only has to think about it and he loses the extra inches on his waist, the bastard.

"What do you mean, and then what?"

"What next? You gonna come with me to the publicity stuff for the book?"

"All of it?" she hedges, sucking in a breath as they start up a hill.

Castle appears completely unfazed about the incline. "Some of it?"

"Some of it," she agrees, lifting her knees to give her an extra burn. Castle keeps up the pace no problem, a trickle of sweat starting down the side of his face. She sighs and turns her eyes back to the path.

"You've been to all the book release parties, but how about the limited engagements?"

"What're those?"

"Book signings, basically, in some of the stores around the city before the book officially releases."

She chews on her lip as they crest the hill, heading for the left-hand path towards the trees, where it's cooler under their shade.

"Do I have to sit by you as you sign books? Act like arm candy?"

"You're no deep-fried twinkie. No, wouldn't make you do the boring stuff. Just. Come hear me speak, give a reading."

"I've been to one of your readings," she says, her shoulders slumping in relief as they get under the treetops, cooler now.

"Yeah, it's like that, but a little more publicity focused. It's critics and stuff."

She huffs a breath and rolls her shoulders to work out the ache right under her scapula. "I can do that."

"Really?"

Kate glances over at him, sees the surprise on his face. "Really."

"That would be. . .awesome."

"Why haven't you asked me to do this before?"

She ducks an overhanging limb and jogs a little faster, waiting on Castle's reply.

"Can we. Talk about this. Later?" he says, and she can hear the breathlessness in his voice.

"Oh."

"It's just. I can't talk. And run. 'Kay?"

"Okay," she says, glancing over at him to make certain that's all it is. But nothing's showing on his face. Still, if he wanted her at these book things, why didn't he tell her?

They jog side by side; she pushing the pace when Castle sounds like he's doing all right, keeping his breathing in rhythm, then slacking the pace when he starts getting breathless again. The flicker of orange afternoon light through the spaces between tree trunks creates a pastiche across the pavement and their bodies as well, an ever-moving jumble of light and dark. She feels the warmth of it dappled on her face.

Castle's always been laid back and nonchalant about the publicity stuff. He tells her where and when he's going, he takes Alexis when she seems interested, but he's never told her that he wants her to be there. Of course, she's never offered to go. It's usually the crowd of people who all read the page six column's speculations about her when she got pregnant, and she's never been sure she can face them, the people who care about page six.

The precinct, her friends, the guys on her squad, her father, her captain. . .they didn't read page six. They didn't read the rumors and the insinuations. Of course, after the first article, Alexis wouldn't let her read them either. Alexis acts as Kate's publicity filter now as well, just as she does for her dad, keeping tabs on the gossip so that Kate doesn't have to read whatever hurtful thing is out there now.

But to face a party filled with people who do?

"Castle?" Does he want her there? Of course he does. He should want her there, a person to stand by him who *doesn't* care what they say about him on page six.

"Seriously?" he whines, but the effect is ruined by the hoarseness of his voice as he breathes roughly at her pace.

"I just-"

"I didn't figure you-" He coughs to clear his throat, turns his head away from her for a second. "-you'd be worried about this."

"Not worried. Just. Why didn't you ask before now?" She's his partner. She should've known; he should've asked.

"Like I said before. 'Bout the splinter." He pauses to navigate a fallen branch in the path.

She dodges it as well and swipes at the sweat trickling down her neck. Her chest is soaked, her arms gleaming with it in the sun. She tucks a stray wisp of hair back behind her ear, using her sweat to keep it slicked down. "The splinter?"

"I told you then. When Dash was born. I'd do this at your pace, Kate."

At your pace. He was waiting on her to get with the program, waiting for her to figure things out.

She blinks through the sudden glare of afternoon light, swallows down the lump in her throat. They break the cover of the trees, and she looks over at Castle in the full force of the setting sun. His hair is burnished, the lines of his face made shadowy and deeper.

Her foot catches an uneven spot in the pavement and she silently curses her distraction as she stumbles. Castle's hand is already at her elbow, steadying her. Kate rights herself quickly, and he lets go just as quickly, as if he was never there.

But she knows. She knows how he's supported her this whole time.

Kate glances down the path for the oak tree at the water's edge, her mental marker for the turnaround of the three mile course she's set for them. Against the setting sun, the tree is a dark and distinct tangle of limb and leaf, lonely in its solitary spot beside the track.

But Kate's not alone. That's what this is about now, what her life means. She's not alone in this.

She wipes at the sweat curling into her eye and glances over at him, her partner.

"A break at the tree, then turnaround to go back," she says, panting now because she's lost the rhythm.

"Good," he grunts, sucking in another breath, apparently to compensate for what he's lost by talking.

She can't help herself. The affirming pound of her feet against pavement, the exertion of muscle, the pull of ligaments across bone and joint, they work together to push her past herself, out of herself, numb to worry or frustration. She can't help herself now. She reaches out a hand and makes a fist in his tshirt, unable to say what she needs to say, unable to stop him, only able to hold on.