She's lecturing him on the merits of Alan Scott - the first Green Lantern - versus the later Hal Jordan when his blue eyes dart over her shoulder and then widen comically.

"Castle, what-" she begins, but he gives a nearly imperceptible shake of his head.

"Rabid fangirl," he whispers, his voice loud enough for her ears only. "Rabid fangirl at ten o' clock."

She furrows her eyebrows, starts to turn, to check out the situation, but his hand clamps like a vise around her bicep, and he tugs her forward. "Quick, kiss me."

And then his lips are on hers, warm and soft and right. And just a little bit frantic.

Her hands land on his chest, his firm chest that radiates heat under her palms. Fingers clenching in the soft fabric of his shirt, she can't help but notice - even when most of her brain is otherwise occupied - how his heart beats so quickly, how it pounds, how it races. She does that to him.

Well, it could be the situation, but-

His mouth moves against hers, drawing her focus back to his lips. Lips, and oh...tongue too. Yeah.

Fangirl must be getting an eyeful by now, but Kate can't bring herself to care, just goes along, pressing closer. She slides her left hand up his chest, her thumb grazing the collarbone left bare by his vee neck sweater, and he shudders, a little gasp vacuuming all the air from her mouth.

Her fingers continue to rise, curling around the back of his neck and squeezing the tense muscles there. He sighs this time, returning her breath, and her heart flips as she feels him lean down, melting into her further.

Castle's mouth continues to work at her, his teeth closing around her lower lip, scraping gently across the sensitive flesh, and it's her turn to suck in a lungful of oxygen.

One hand still at her bicep - though looser now, his thumb brushing the juncture of her arm and shoulder - his other drifts to her lower back, fingers glancing along the waistband of her jeans, along the border between her silky blouse and her comfortable denim.

He needs to stop that. She needs to make him-

This is a public-

But ohhh, warm, nimble fingers delve beneath the hem of her shirt, stroke her skin. And she tries, she tries, she tries. But when his middle finger starts tracing circles just above her sacrum - she can't. She bucks toward him, their lower bodies connecting as their mouths separate with a soft pop.

"Castle," she tries to reprimand him, but it comes out breathier than she intended, a moan rather than a reproach.

He cradles her, his hand rising - above the fabric this time - a little higher on her back, the other palm sliding from her arm to curve around her shoulder blade.

"I think it worked," he murmurs, mouth at her ear, warm breath cascading over her skin, sending tingles to all of her extremities.

He pulls back then, lifts his left hand to brush a lock of hair behind her ear, the gesture so familiar, so tender. "Thank you. You probably just saved me from a terrible fate."

She slides her own hand from its resting place at his neck, coasting it over his shoulder, his bicep, his forearm, until she can curl her fingers around his where they rest on her shoulder.

"You know," she drawls. "You do have other options."

He smirks. "Do I?"

"All you'd need to do is flash this," she says, running her thumb slowly over the smooth, warm metal that graces his third finger. "And they'd know you're off the market. That you're mine."

He nods, face solemn even as his eyes sparkle. "True."

She steps back, expecting him to remove the hand that still grips her waist, to let them both carry on with their day. She'd caught him during a break at one of his book signings to get his perspective on a case, not to debate Green Lantern incarnations with him, and definitely not to fend off the advances of some fangirl.

But his grip doesn't slacken, and his eyes flick from her face to a point somewhere over her shoulder.

Kate turns her head, expecting to spot his fangirl, to see some young thing, or even possibly a middle aged mother of three observing them from a badly concealed nook, disappointment or heartbreak or even disgust etched across her face.

There's no one. Just an long aisle of shelves. Lots of books. No people.

"Looks like she left," Kate says with a shrug.

But when she turns back to her husband, he wears an expression that looks far too much like guilt. "Castle?"

He says nothing. And that's answer enough. She narrows her eyes when he meets her gaze, his eyes wide, but a little defiant all the same.

"There was no fangirl, was there?" she surmises, poking a finger into his chest. "You made her up."

He lifts his hands, a gesture of supplication. "I need to get my eyes checked?"

The detective scoffs, and he sighs. "Fine. I wanted to kiss you."

She shakes her head, remembering his hands on her skin, the fevered touch that drove her hips into his. "You wanted to do a lot more than kiss me."

"Can I help it that you're hot when you argue with me about fictional characters?"

She lifts an eyebrow. "Only then?"

His grip loosens, finally, and his hand skates up her side, warm and appeasing, his voice low when he speaks, an arousing growl that curls in her belly.

"All the time," he amends, his expression properly humbled. Humbled, but still teasing - just the way she likes. Humbled, but still tender - just the way she loves.

She nods, pursing her lips, lets her eyes soften as she looks at her silly, wonderful, sexy man. Her husband.

"For future reference," she murmurs after studying him for a moment, pushing up to press her chest against his and letting her lips brush over his earlobe. "If you want to kiss me, you don't need a cover story."

"That so?" he rumbles, his hand dropping to her thigh, fingers kneading at the muscles underneath the denim.

"Mmm," she affirms. "I think we're long past the need for dumb ideas."