He can't help but laugh when she comes running into her living room, a towel clutched around her chest and shampoo still clinging to her hair. Water drips steadily on the floor as she stands in the middle of the room, staring at him with an open mouth.
"What the hell, Castle?" Her voice is loud and forceful and he knows it's a more than slightly desperate attempt to distract them both from the music pouring out of her stereo.
"I never pegged you for a Hanson fan, Beckett."
"I can't leave you alone for twenty minutes without you snooping through my stuff?" Her righteous indignation is undercut by the bouncing beat of bubblegum pop and he laughs again, his whole body shaking with the force of it. "What the hell is so funny?"
Castle smiles and she glares at him, a clump of bubbles slipping from her hair and making a slow slide down her left shoulder. Wordlessly, he points at the speaker with one hand as he presses the little button on the dock with the other, the music getting louder, gibberish lyrics cutting through the crisp morning air. He bends his knees and wiggles his hips in a silly little dance that sends his robe fluttering around his calves, the ends of the belt swinging against his thighs. He can see her fighting back a smile, her lips pressed tightly together as he shimmies his way across the room, necking swaying wildly to the jumpy rhythm of the song.
Her laughter breaks free when he slips in the puddle spreading out around her feet and collides with the wall, a surprised grunt hanging on his lips. He bounces off the stones, hip and shoulder burning, and grabs her around the waist, the terry cloth towel damp and rough against his forearm.
"My pain is humorous to you?"
Kate nods at him, her eyes shining. "It is when it's karmic payback for mocking my music library."
"It's Hanson, Beckett. I'm obligated to mock." He trails a finger across the exposed skin at her collarbone, drawing a path through the evaporating water and drying soap. "Plus, you don't believe in karma."
"No, but you do which means I get to use it against you when it's convenient."
"You're mean."
"And you're a snoop." She swats at his chest, lips curling at the edges. "What have I told you about that?"
"That I can only poke around in your stuff with express permission and supervision. To be fair, though, I was just looking for something to listen to while I made breakfast." He nods over to the island, a mixing bowl and carton of eggs laid out on top. "So I wasn't technically snooping. Plus, if you wanted to hide that, you should have named the playlist a little more creatively."
"'Happy' is a perfectly fine name for a playlist. And I wasn't hiding anything, I just didn't expect to be blasted out of the shower by nineties pop." Kate pries his arm off her waist and spins, walking toward the bathroom. "I'm going to finish my shower now."
He stares after her for a moment and then follows, picking his way carefully around the puddle while tugging at the belt tied around his waist. The shower curtain hangs half opens, water pummeling the buttery yellow tiles; he watches her climb into the tub and then follows, tugging the curtain closed behind himself, smiling when she leans back against his chest and sighs.
"So," he starts, reaching out for her body wash and pouring a generous pool onto the loofah she's holding out for him, "which one was your favorite? Isaac? Taylor? Please don't say Zach, though, because that's creepy."
Kate turns around and runs the soapy sponge over his chest, her voice full of laughter. "No, Castle, what's creepy is that you know their names."
Castle shrugs and pulls her closer, his hands roaming freely over the wet plane of her back, dipping down to coast over her ass and thigh. The song fades out as his mouth hits her neck, teeth scraping along the long column of soft skin. She groans against him as the song starts over, the strains of the happy guitar filling the tiny room.
"Did you have to put it on repeat?"
"Yes." He twists them and pushes her up against the wall, hand slipping down over her slick stomach. "Now come on, Beckett, let's defile some precious late nineties memories."