"What's the rule?" Beckett groaned against his neck as he stroked heated palms down her sides and feathered kisses along the column of her throat.

"No funny business in the precinct?"

"Yes," she let out, in what was probably meant to be a stern warning; it came out more like a moan of encouragement instead. He had almost gotten one hand down the front of her pants when the stairwell door banged open and Ryan materialized, balancing a stack of folders and humming.

He almost dropped the folders when he caught sight of the two of them pressed up against the wall.

"Whoa, g-guys!" He fumbled for his voice, and his folders, while his gaze swept over their disheveled appearance before fixing on a spot on the wall half a dozen inches above Castle's head.

"The elevator – it – I'm just going down to Records," he mumbled at the wall. "Um, don't take the elevator until maintenance has had a chance to check it out – okay – have a great day – bye."

He fairly flew down the stairs, folders clutched to his chest.

Castle stared at Ryan's fleeing form for a second through the rapidly-dissipating fog of lust that was clouding his brain as he belatedly searched for an excuse for why he was in the stairwell with his hands all over his partner.

"Uh, we were just…doing something…for the case," he called after Ryan lamely, leaning over the railing to peer at him. "That's all! Ryan?" But the detective was already two flights down and rapidly disappearing from view.

Sighing, he ran a hand through his mussed hair and turned back to Beckett, an apology ready on his lips, but she was already gone.

Shit, she was going to kill him.

When Castle finally slipped back into the bullpen after five minutes of intense deliberation in the stairwell – should he go back inside and face Beckett's wrath? Run after Ryan and buy his silence with Yankee tickets? Escape to the loft, down a fifth of scotch, and bury under the covers? Invent a time travel machine and go back? – he found Ryan flipping through phone records at his desk while Beckett and Esposito briefed Gates on the latest case developments in her office. Beckett looked every bit her usual cool, impeccable self. If her pulse was still racing like his was, she was hiding it well.

He pulled up a chair next to Ryan's desk, where the detective was intently avoiding his gaze.

"Hey Ryan, about earlier–"

"Dude, don't worry about it." He continued scanning the page, still looking a little traumatized from having interrupted Mom and Dad's alone time.

"But–"

"It's fine, Castle. I won't tell Gates."

Castle resigned himself to staring at the side of Ryan's head and willing the detective to meet his eyes. Funny, this usually worked with Beckett.

He's silent for all of thirty seconds. "Aren't you at least a little curious what's going on?"

"Well," Ryan hedged, meeting his gaze at last, "it has been a little weird between you two lately." When Castle didn't move to interrupt him, he continued. "You don't argue with her about who drives nearly as much. And you actually shut up when she tells you to." He paused, looked away. "You guys aren't fighting again, are you?"

"What? No! No. I've been behaving better because – well, let's just say the pool you guys have going can be closed now."

"Huh?"

Castle shot Ryan a reproving glare. Here he was baring his soul to the man and he was playing dumb.

"The pool on when Beckett and I were getting together."

Esposito strode around the desk and dropped a folder onto Ryan's stack. "That's been closed for ages, bro."

"What?" Castle's head swiveled to take in the other man. "Who told you, Lanie?" Had Beckett told Lanie?

Esposito plopped down in his own chair.

"Nah, Lanie denies knowing anything, but she has a strict hos before bros policy. Whatever she knows, she's not telling."

"Then how did you–?"

"Give us a little credit, man," Ryan cut in, puffing up his chest. "We're detectives. We've been on to you guys for ages. Only reason we haven't said anything is because," Ryan tilted his head in the direction of Gates' office, "you know. Plus, Beckett would probably have us both killed."

"Wait, what do you mean, ages?" It hadn't been that long since the thunderstorm deposited a soaking Kate Beckett on his doorstep.

"Well, since last fall, at least."

Castle knew he looked ridiculous with his jaw hanging open but he couldn't seem to shut it. Ryan ignored his look of disbelief and pressed on, checking off the evidence on his fingers.

"Beckett gets shot, we visit her in the hospital, everything's fine. Then she breaks up with Josh, severs all communication with us, checks out of the hospital and retreats to her dad's cabin. Then two days later you let Gates kick you out of the precinct."

"I – I didn't even know she'd broken up with Josh. Or that she was at her dad's cabin."

"Right. And then she reappears in the fall. A few days later, Gates takes you back."

Castle sputtered as the two detectives shook their heads at him. "You know, you guys are not really as sneaky as you think. All the talk of writers and muses fighting crime together."

"That time you were trapped in the bank and Trapper John referred to you as Beckett's boyfriend and she didn't even try to deny it."

"That huge fight you guys had that left Beckett crying while you chased Slaughter around town."

"We did not have – Beckett was crying?"

Esposito just shot him a dirty look.

"Beckett getting jealous of your CIA ex-girlfriend."

"Sharing custody of a dog."

"Slow-dancing at Ryan's wedding."

"Those looks Beckett gives you when she thinks you're not looking."

Beckett – he had to find Beckett. God, she was going to kill him and it wasn't even his fault.

Castle found her in the break room fussing with the espresso machine. He paused on the threshold for a moment, watching her nimble fingers fly over the apparatus. But then she growled under her breath as the steamer hissed and he snapped into action.

"Here, let me do it," he crowded her from behind and got a sharp look in response.

"Stop it. Are you trying to look suspicious?"

"It's kind of too late for that," he muttered in response.

She tucked a strand of hair behind her ear. "I know Ryan. He won't tell."

"He doesn't need to."

"What?" She spun on him, cutting eyes at the bullpen, where Ryan and Esposito were deep in conversation. "What'd you tell them?"

"Nothing!" His hands came up in a gesture of surrender. It was probably wise to omit the part where he did in fact almost spill the beans. "Ryan and Esposito think we've been together for ages. Since last summer, in fact."

Beckett's mouth hung open but no sound came out. "What?" she managed at last. "I didn't even tell Lanie!"

"Apparently Lanie operates under some lady code that–"

"Shhh." She was shushing him, hand raised imperiously, which probably meant she wasn't going to shoot him after all. Castle breathed a sigh of relief.

Beckett was worrying her lip, brows furrowed. "If the pool's closed, where's my money?"

"Where's your – wait, what? You bet on us?"

Beckett shrugged, her lip between her teeth. "I got a little buzzed one night, insisted they let me in on it. Plus, I knew it was only a matter of time anyway."

Castle gaped at her.

"Come on, Castle. This thing between us? Serena Kaye saw it. Kyra Blaine saw it. Natalie Rhodes saw it. People who work with us on a single case can see it. People who have never even met one of us assume we're together." She paused, a smile tugging at her lips. "Special agent Jordan Shaw – who profiles people for a living – could see it. I might have been in denial, but I'm not stupid."

Castle could feel his jaw beginning to complain from dropping open for the umpteenth time that day. If he had a dollar for every time someone had rendered him speechless in a span of mere hours – he would have a lot of money. Maybe enough to fund his hypothetical time machine.

"You know, you could have told me."

He could hear the laughter in her voice. "Yeah, but where's the fun in that?"

Smirking at him over her shoulder, she dug a tattered piece of paper out of her back pocket and sauntered into the bullpen, headed for Esposito and Ryan. She glanced back at Castle and held up the piece of paper, quirking an eyebrow.

"Want to go to Remy's after work? My treat."