A/N: Thank you for sharing how much you're enjoying this story. You might recognize a couple of lines woven into this chapter. ;)

Slow Burn

Chapter 4

"Whoa there, cowboy!"

Kate holds out her hands, catching Castle in the nick of time. He's moving so fast that it takes all her strength to avert a painful collision and keep them both standing upright.

His momentum just keeps throwing them together today.

The shocked look on Castle's face and the lengths he goes to avoid touching her are the twin thoughts that register in Kate's brain. His body feels rigid under her hands, the power in his muscles equally arousing and concerning. Instead of pleased to see her, he seems to be in full fight or flight mode.

"Hey," she says softly, smiling at him. "You okay?" She tilts her head to one side waiting for an answer. When she flexes her fingers at his elbows, he jumps.

Mutely, Castle continues to stare at her. Though she couldn't say when or how she started touching him here, she rubs her hands lightly over his ribs to bring him around. Maybe she was drawn to the baby-soft cashmere of his sweater, which is currently caressing the underside of her fingertips, who knows? She likes the feel of him: soft and powerful at the same time; no further explanation required.

"Castle?" she says quietly. "What's going on? Were you…" she frowns and shakes her head slightly, "…heading out somewhere? I heard your mother say she wasn't going to wait up."

This does it. As she repeats Martha's parting shot, the potential twin meaning behind these words dawns on both of them. Is he going out to spend the night? She thinks he's going out to spend the night? His mother's a meddler, unconscious and not. This could go either way.

"Oh." Kate drops her hands to her sides in disappointment and bends to retrieve her helmet from the floor. "So stupid. I should have called," she mutters to herself, rolling her eyes.

Stirred by the creak of her leather jacket and the sight of the black bike helmet dangling from her fingers, Castle finally speaks up. "I was coming to see you. And you were obviously…"

"Coming to see you," Kate says, smiling with relief.

Castle lowers his gaze from her lips to her hands. "Did you come here on your Harley?" he asks with awed excitement. "To see me?"

Kate nods, raising the helmet to stomach level so that it sits between them; a pregnant pause.

Martha's cultured, dramatic voice pierces the warmth of the moment they'd quietly been sharing. "Okay, I think we've thoroughly established that you both needed to see one another. Now, how about you invite darling Katherine inside, Richard? I know we live on the penthouse floor, but nothing good ever came of standing out in the hall. The feng shui is all wrong for one thing."

Kate's face is a picture: an attractive blend of embarrassment, amusement, and a sympathetic smile that says she feels bad for him. Again.

"Mother!" Castle groans in exasperation, covering his eyes. "We don't need your help. Thank you very much."

"Oh, darling, I think all the evidence says that maybe you do. Katherine? Yoo-hoo!" Martha calls out from the living room. Castle silently shakes his head, urging Kate not to engage with his mother.

"Hi, Martha," Kate replies, poking her head through the open door to give her a wave.

"Dammit, but you're too polite," Castle hisses at Kate and she shrugs in return, whispering, "I can't just ignore her." Castle nods theatrically. "Oh, yes, you can."

When he feels Kate's hand close around his wrist, he looks down to confirm that she's really touching him. When he up at her face, she's staring into his eyes. She purses her lips, hesitating on a thought before speaking. "Want to get out of here? Go somewhere we can talk? Alone. Without an…audience?" she says, pointedly cutting her eyes to the open door.

Castle is nodding vigorously before she's even finished speaking. "Please? Oh, God, yes, please. I would like that very much."

Kate laughs at his vehemence. She strokes the silky underside of his wrist beneath the cuff of his sweater with her thumb, soothing and arousing him at the same time. "Were you planning on going out like that?" she asks, giving him a slow perusal from head to toe that has his heart missing a beat or two. She doesn't even try to hide the fact that she's checking him out, not like she does at the precinct sometimes when she thinks he isn't paying attention and he catches her staring.

He pats his sweater and his legs, looking down at his clothes in frantic alarm as if he's forgotten something crucial, like pants. "Is this not okay? Should I change? Are these slacks too smart? You don't like the powder blue?" he asks in a panicked rush of self-criticism because she's wearing sexy, skin-tight denim and black leather, the ultimate in badass cool, and he is…well-dressed and expensive. He hopes he doesn't look like some rich sugar daddy.

But Kate just laughs again, amused by how much he's freaking out on her right now when he was braver and more reckless than either of them has ever been just a couple of hours ago. She grips his forearm and leans closer. "Castle, I love the sweater…on or off," she whispers, allowing her eyebrows to rise, adding extra meaning. "The color really suits you." She winks and his throat bobs. "I just meant that you might want a jacket. It gets pretty cold on the back of the bike. Even in summer."

She catches him swallowing again. "On the b…bike?" he stammers. But she is completely unfazed, watching him coolly. "You want me to get on the back of your Harley?"

Before Kate can answer, Martha calls out, "Darling, with your back problems, do you think that's really such a good idea?"

Kate pulls him to her and hisses, "Rick, go get your leather jacket. Now! We are getting out of here." Then she turns him around and gives him a shove towards his own front door.

She walks away to wait for him by the elevator after calling out an unequivocal farewell to his mother. They need to do this by themselves, without an audience, and certainly without his mother's "helpful" commentary.

Seconds later, Castle comes jogging out through the front door carrying his leather jacket. He's out of breath and the look on his face is alarmed at first until Kate calls out, "Over here!" and it relaxes into a grin.

"Thought you'd taken off on me for a second," he admits with disarming honesty. "And I wouldn't blame you if you had," he adds, jerking his head in his mother's direction.

Kate bumps his shoulder as they wait for the elevator to arrive. "Hey! Partners," she says, feeling a pang deep in her chest when she sees what that single word can do to him, to both of them really. "I just had to get away from..."

"My mother, yeah." Castle runs a hand through his hair, disturbing its perfect layers. "And don't even think about apologizing," he tells her when she opens her mouth to do just that. "I love her dearly, but tonight she is well out of order."

"I'm sure she just wants the best for you…for us," she amends, because there can be no pretending that his mother isn't fully aware of what went down at the precinct today. "But…I think we need to sort things out for ourselves, don't you?"

When Castle nods, she can have no idea the swell of gratitude welling inside him to hear that she cares enough to rescue him from his mother's browbeating interference. Most women he's been with have sided with his mother against him, but Kate takes his hand when the elevator doors open and draws him inside along with her. He's so giddy on the brief decent that it feels as if they're falling to earth, only to land on a feather bed made out of love. He doesn't mind admitting, after the wild events today, that he might just be losing his mind. It feels great.

The Harley Softail is parked by the curb, and Castle's doorman, Eduardo is out front keeping an eye on it. Or really coveting the motorcycle would be a more accurate description since he's stroking the leather seat and admiring his reflection in the chrome headlamps. He salutes Kate after he hands her the spare helmet she left in his care, then he makes himself scarce.

When Kate turns to give Castle the second helmet, she finds him standing in the middle of the sidewalk just staring at her bike. He's holding his leather jacket to his stomach, but he's made no move to put it on.

"Hey, you okay?" she asks him for the second time tonight. She follows his gaze to the bike. "You happy to ride with me? I mean you don't have some pathological hatred of motorcycles, do you?"

Castle shakes his head and shrugs into his jacket. "No, it's not that," he says with a more deflated tone than she expected when she decided to ride over here tonight and bring a spare helmet just in case.

Kate takes a step closer. "Castle, talk to me. What's wrong?"

He drops his head for a second, almost shameful, then he takes a breath and looks up at her. "It's just I can't help wondering…how many guys have been here before?" he admits with sad eyes trained on the back of the Harley-Davidson.

Kate nods slowly, surprised but letting his confession sink in. Coming from Richard Castle, it's a rare display of a lack of confidence and that makes it kind of sweet. "Right." She stands straighter and looks him in the eye. "Well, I'm not going to deny that I've had other guys on the back of my bike before. But, Castle…none of them were you."

Her smile breaks the tension, and when she holds out her hand to him they both laugh and he comes to her freely. She tugs the front of his jacket around him and pats his chest. "Come on. Zip up. The West Side Highway's calling our names."

Kate throws her leg over the bike and eases it off the kickstand. She hits the start button and the engine roars to life. When she squeezes the throttle a couple of times, Castle feels the wall of noise hit his chest and he wants to howl at the night sky, but he pulls on the helmet, instead. It's a tight squeeze. He swears he doesn't have an abnormally large head as his mother has always complained - "why do you think I had an elective cesarean in the 70's Richard, back when the word 'elective' had most people asking about voter registration?" – and it'll probably ruin his hair, but tonight he doesn't care.

Once he's settled behind her, Castle doesn't know where to put his hands, so he rests them on his thighs. Kate's helmet is still hanging on the handlebar and she turns to speak to him. "In case you haven't done this before, just lean when I lean and hold on tight. Okay?"

From what she can see of his eyes with the visor up, Castle looks nervous, but he nods. She smiles again to try to get him to relax and squeezes his quad, which is rock hard beneath her fingers. "Trust me, okay?"

"Always," he says thickly, suddenly overcome with some deep emotion that surfaced the second he opened his front door to find her out in the hallway tonight. His mother was right for once: she didn't run, or if she did it was straight back towards him.

"Hey, I said hold on tight," she reminds him when his hands remain glued to the front of his thighs.

"Right. Like…like this?" he says, tentatively placing his hands on her waist.

"If we were total strangers, yeah," Kate snorts. She takes his hands and wraps them around her middle so that he's hugging her. "When we really get started, might be better like this so that we're one: you, me and the bike."

So that we're one. Wow!

"You…you want me to hold you that tight?" he checks. "You're okay with that?"

She turns to look at him, her boots firmly planted on the asphalt, holding them up. "Rick, in case you've forgotten, you proposed to me today. I think it's safe to say you can put your arms around me and I won't freak out. Now, give me some room while I put on my helmet."

He watches in awe as she tips her head back, shakes out her hair so that the ends tumble over her shoulders and brush the front of his jacket before she tugs her helmet over the cascade of dancing curls. The bike throbs beneath them and Castle finds the vibration unquestionably erotic, especially with Kate Beckett astride the chrome beast with him, her thighs spread either side and her bravest self on display.

She makes a thumbs-up sign and Castle drops his hands to her waist. "You ready?" she yells above the din.

"Ready," he yells back, fighting to keep the grin off his face.

Soho's broken roadways have him gripping Kate tightly without having to be told. Between the potholes and the sections of original cobblestone surfacing now and again from beneath the melted blacktop like archeological remains, Castle worries that he might be crushing her. But he worries more that he might fall off, and besides, it's not every day he gets an open invitation to wrap his arms around Kate Beckett and hold her tight.

The good news is that he doesn't hear Kate complaining, and by the time they reach West Street, he's relaxed and starting to enjoy himself.

The West Side Highway runs parallel to the Hudson River from the southern tip of Manhattan to West 72nd Street. They join at West Houston onto the three-lane stretch that heads north. They catch glimpses across the river now and again between buildings and gaps in fences. Lights twinkle over in Hoboken, New Jersey, and Castle watches an airplane pass overhead on final approach to Newark Liberty. Everywhere he looks, the night is beautiful, the sky dark as velvet, and his head bursts with poetry.

Traffic is mercifully sparse, and they hit a run of green lights so that the only time they're forced to slow down is beside the Javits Center at West 34th Street after a fast, straight ride over thirty exhilarating blocks.

Castle is disappointed to have to lower his feet to the ground at the red stop signal. He had his chin resting on Kate's shoulder until then, his arms tight around her middle. He could swear he felt her heart pounding even through several layers of leather with her perfume tickling his nose. She feels so perfect in his arms: slight and yet powerful with his chest pressed against her back. He's never loved her so much; his heart is fit to explode and now he doesn't want to let her go.

He whoops aloud with the rush of it all when the bike finally stops, and Kate turns her head towards him. He can hear her laughter bubbling from beneath the tinted visor and he feels her body shake with it.

"How much further do you want to go?" she yells over the noise of the engine, dropping her hand to his thigh.

"I'd do this all night if I could. How about Canada?" he says, clearly not thinking straight, and Kate laughs again and squeezes his leg.

If she moves her hand any higher, he might just pass out.

"Okay, but how about we stop for coffee or something?" she suggests. "Somewhere we can talk."

His chest tightens and his mouth goes dry when she mentions of the "T-word." Castle knows they need to talk. Damn, he started this with his ill-judged, poorly-timed proposal. Was it really just today he dropped to one knee in front of her? But now you're here, Rick, he reminds himself. She's never asked him to take a ride with her before, and now you're here. So maybe talking will be a good thing. Maybe she's not doing all this just to let him down gently. Maybe getting to hold her tight on the back of her Harley isn't a consolation prize; maybe it's progress.

Whatever, it's time to tap into his brave, reckless streak again and find out.

"Pull over wherever you can," he says confidently, giving her a thumbs-up sign of his own. "You're right. We should talk."

TBC...