Disclaimer: The only part of Castle that I own is the TV on which I watch the show.

A/N Please note: this story is rated M.

She starts as soon as they've closed their front door, even before they've taken off their coats, piercing him with a ferocious scowl.

"You are in deep, deep trouble, Castle," she says through clenched teeth. "I mean it."

He's mesmerized as she laces into him. Her cheeks are a luscious red, almost exactly the shade of a pomegranate, and it's wildly distracting. Not a word is getting through until he realizes that she's hissing. Even without any sibilants like "zip it," "stop," or "shit"—all of which she has used any number of times when she has been mad at him—she's hissing.

"I can't believe you did that. It was mortifying."

Did what? All he knows is that the flush in her cheeks has changed to the color of a Rome Beauty apple. If she were Italian that would be even better, a Rome beauty! Dammit, he needs to pay attention to what she's saying and stop reveling in how spectacular she looks when she's like this. Particularly when she's hissing like a snake, some hypnotic, slithering reptile that could strike him at any second. A cobra, maybe, or a Black Mamba. Or an asp, like Cleopatra, even if that's a myth. God knows Beckett is as gorgeous as Cleopatra must have been.

"Castle!"

"Huh?"

"Are you listening to me?"

Ah, there's a sibilant, "listening," and she's leaning on it just as she's leaning in to him. Her face is inches away. "Sorry, I'm sorry, Beckett."

"Really? And for what, exactly, are you making this heartfelt apology?"

Oooh, Scotch bonnet chili peppers, the reddest, hottest things he's ever seen: that's what her cheeks are like now. The true danger zone. He's gotta snap out of it. "I mean it. I do. I couldn't be sorrier."

"What did I just say, Rick?"

God help him, he has no idea, but he'll be contrite, even if he can't confess to a specific transgression. He puts his hands up, palms out, in surrender. "I don't know. I don't know. But it's because you look so hot—I mean hot in the best way, not hot as in overheated, but hot as in sexy—that I couldn't quite pay attention."

Her expression hasn't mellowed one whit. "You are totally fucked, Castle," she says, stalking to the kitchen.

She's wearing his favorite killer heels today, and oh! the view from behind. He follows, loops one arm around her waist and pulls her hard against him. "I look forward to being totally fucked again," he says, nuzzling her neck, "preferably right now, by you."

"Dream on, buddy," she says, simultaneously wresting herself from his embrace and opening a drawer to extract a corkscrew.

He has misjudged her mood, underestimated just how bad it is. She's in a fury, a flaying three-layers-deep anger, and she pulls on the door of the wine cooler with such force that he's surprised that it doesn't come off its hinges and crash onto the floor. He watches with a mix of wonderment, confusion, and fear—yes, fear—as she seizes a wine glass and slaps it on the counter next to the bottle she had chosen. Only now he can see what it is. Geez. A 1982 Château Lafite Rothschild. $1,925. Per bottle, not per case, though admittedly he had indulged in a case.

She opens the bottle with such intensity that he thinks she could have gotten the cork out with her bare hands. And now what? She's pouring the wine without letting it breathe? He can barely breathe himself. Oh, okay, she's using the aerator. Still, that one glass of wine is worth almost 500 bucks. She should have let it breathe naturally. It's probably best that he not comment.

Apparently she's planning on drinking alone, since she had taken only one glass from the rack. He'll ask, very politely, if he may join her. Before he has a chance, though, she storms wordlessly to the living room and sits down, bristling, in a chair. She hasn't looked at him since she entered the kitchen. He quietly pours himself some wine and walks to the living room. She deliberately chose the chair to prevent him from cuddling up to her. All right, he'll just drag another over and put it next to hers.

"Beckett?"

Nothing but blistering cold.

"Kate?"

She takes a sip, but doesn't react. It might as well be Welch's grape juice that she's sampling rather than a freaking 1982 Château Lafite Rothschild. She should be licking her lips, showing the tip of her very pink tongue, making obscene little noises that produce filthy images in his mind. Her eyelids should be fluttering. He shouldn't be thinking about this.

"Kate, I want to apologize, but I don't know what I did."

She whips her head so fast towards him that he's grateful that her hair is pulled back. If it were loose, it could have grazed his cheek and left a burn for days. "You don't know what you did? Unbelievable." She turns away again, so she's in profile. It's tough to read her well if he can't see her eyes.

"Believe me, I don't."

Her posture is rigid and that wineglass stem is in danger of snapping in two. "It's what you said to Esposito, Castle."

"When? I mean, I talked to him on and off all day."

Now she turns slowly, by fractions of a degree. It might be tomorrow by the time she's finally facing him. "When. You want to know when?"

"Right. When I said whatever terrible thing I must have said."

"Let me refresh your memory." Her diction is Henry Higgins-like in its precision. "On our way to the crime scene this morning we were talking about trying to schedule our wedding. I said, 'I want to be flexible.' You laughed with this leer on your face and said, 'You already are flexible.' Espo heard you and asked what was so funny. You said, 'Well, actually, did you know Beckett can lift her—' and I stopped you."

It's beginning to come back to him. All the painful way back. He's uncomfortably 99 percent sure that he knows what's about to happen. "Yeah, and I stopped. I did."

"Damn straight you did. But you couldn't leave it alone, could you? So you said to him, 'I'll tell you later.' I told you no and you agreed, but that didn't stick, did it? Because about an hour ago when we were getting ready to come home, I heard you tell him. Every syllable is burned into my brain." She pressing her fingertips into her forehead as if she were branding a calf.

"Oh."

" 'Oh'? That's it? Your explanation?"

He's the only dead man with a pulse rate of 60. Maybe more like 120, given how nervous he is at the moment. "In my defense, I didn't tell him everything." Oh, wrong thing to say.

"Your defense is that you didn't tell him everything? Jesus Christ, Castle, do the two of you hang out in some metaphorical high-school locker room? For starters, what you did was indefensible. I asked you not to say anything—and by the way, at this stage in our lives, not to mention our relationship, I shouldn't have to be worrying about you doing something like that—and you said you wouldn't."

When she dips her head and covers her face with his hands he really is ashamed. But hell, he hadn't said much to Esposito at all. Not in the general scheme of things. Not what she really is capable of. It stuns him almost every day, though it's a good bet that today won't be one of them. Maybe not any time for the next week. "What I said was just a mild but flattering observation. You know, that you could lift one leg straight up in the air when you had the other leg flat on the floor."

"Bed."

"What?"

"You said when I had the other leg flat on the bed."

"Okay, bed. But everyone knows you do yoga, so it's not like I was, uh, revealing anything. Basically I was just saying you're so flexible you can do a split. You know, like a cheerleader."

She has taken her hands away from her face, and her eyes are so fiery they could remove paint. "A split while we're having sex and I'm naked, Castle, not a split on the basketball court in my little skirt and sweater."

Why did she have to say that? Now he's alternately picturing her with no clothes on, or in a little skirt and little panties and the tightest, skimpiest sweater in history. And when she's angry, as she is now, she's radiating pheromones, at least for him.

"And furthermore."

Oh, shit, there's a furthermore?

"You didn't just say I could put my leg straight up in the air, but that I could put it past your ear."

It's true. "I did. I'm really, really sorry. That was completely inappropriate."

"No kidding, Castle. As far as I'm concerned you shouldn't be having that adolescent conversation with anyone, but especially not with my co-worker, someone on my team, someone who reports to me. Besides that, he's now imagining me—oh, God, I'm so embarrassed."

Her cheeks are red again, a nice match with the wine, but she's glaring at him again, too. Maybe it's time to own up to something, to clear the air. After all, they're getting married, and he has to set this right. "I have, um, I want to—may I make a confession?"

"I'm hardly your priest, but go ahead."

"I'm not asking for absolution."

She's still glaring.

"Fine, maybe I am asking, hoping for it. Forgiveness. Here's the thing, Kate. I might have been—okay, I was—bragging a little bit. I hadn't intended to, I promise."

"Your promises aren't worth much at the moment," she mutters, but at least she's not glaring any longer.

"It's just, well, for a long time I've harbored this tiny, secret fear about the two of you."

"Two of who?" She's genuinely puzzled.

"You and Esposito."

"What about us?"

"That you were together. Back when. Stupid, right?"

"Monumentally stupid. You don't think I learned anything after that disaster with Royce? That was the definition of a rookie mistake. Give me some credit."

"But—"

"Besides, I was never attracted to Espo. He's always been like a brother to me."

He's surprised. "Really?"

"Yes, reallllllly. Got it?"

"Got it."

"Is that what this is about? Jealousy? Of something that never happened? And even if it had—and I assure you, it didn't—this is insane, Castle. We're engaged."

"I know, I know. But that's just it. Every day I wake up and look at you and can't believe that there you are in bed with me, or standing in the kitchen making scrambled eggs, or reading a book in the office with that little frown you get, or brushing your teeth with your hand on your hip, wearing nothing but some ratty old tee shirt of mine. Or discussing nail polish with my mother, of all people. Do you see?"

She doesn't answer, but her eyes are soft.

"I can't believe that I finally got the woman I always thought was out of my reach, Kate. Not an hour goes by without my being amazed that you chose me. And you know how Espo loves to needle me. He makes little digs at me all the time, and I guess I was getting back at him in a way that meant something to me. And I was a jerk."

"Yeah," she says. He's pretty sure that there's a smile there, even if it's not actually visible.

"I really am sorry, Beckett. It won't happen again. "

At some point she had kicked off her shoes, and she's pointing her foot at him, extending it until her toes are wiggling underneath the hem of his jeans. "I know." She waits a beat. "And if it does, I will snap your neck between my legs. Just like that. I can do it."

He decides to risk it, and grabs her foot, moves his hand up to her ankle and starts dragging her slowly off her chair and onto his lap. "This leg?" he says, squeezing her thigh. "The one I was talking about when I shouldn't have been? The only shoulder this leg is ever going to be on again is mine."

"You think?" she asks, returning the squeeze. "You love that position, don't you? You love what you do to me in that split. The way I scream for more." She leans forward, bites his ear, and lets her voice drop an octave and her hand drop into his lap. "My leg could be on my shoulder, you know. On my own shoulder. You've seen me do that plenty of times, haven't you? When I'm rolled up under you like a contortionist, all quivering and slippery. You like that, don't you?"

He's moaning a little. "Yes, yes I do. I like that."

"I'm very flexible, Castle." She's straddling him, her knees gripping his hips like one of those jaws-of-life machines at a traffic accident. "I can feel your adductor muscle here," she says, unzipping his pants and running two fingers along the inside of his upper thigh.

Now he's not exactly speaking, more sounding, making a strangled sound. Something like "muurggh."

"I know a lot about anatomy," she says, still stroking his thigh but scratching, too, with newly manicured nails. "Muscles, especially. You have to, if you're flexible and don't want to hurt yourself. Or your partner." She moves her hand up, palms him and squeezes more lightly. "Like your cremaster muscle." He jumps. "Have to watch out for that, Castle. Be very careful of that."

He's barely hanging on for want of her. When she wraps one leg tight around the middle of his back, and digs her heel into his scapula, he manages to ask, "Just how flexible are you?"

"Oh, I think you know," she says, her foot pressing harder into his spine. "I think you knew when I did that backbend over your shins the other night. 'It's like rocket thrust,' you said. Felt like a thousand pounds of rocket thrust. I was flying. You liked that view, didn't you?"

"Rgffhh." She's rocking against him now, and wait! His eyes shoot open and he finds his voice. "Your pants?"

"Right, Castle. Took 'em off. Glad you noticed."

"How?"

"I'm flexible, remember?" She's kissing him behind the ear, and still rocking. And then she's not. She's not on his lap. She disappeared.

"Beckett? Wha'?"

"Get up, Castle."

"Up?"

"Out of the chair!" She pulls on his arm until he's on his feet. "Now take your clothes off, and stand right here."

While he hurries out of his, she takes off the rest of hers, a soft top and a bra. And then she puts her shoes back on. He has no idea what's going on, but it's promising. The naked-except-for-five-inch-fuck-me shoes is definitely promising. They're standing by the sofa, and she raises one leg to put her foot on it. "Good," she says, licking her lips as she looks at his impressive-if-he-does-silently-say-so-himself erection. "You're ready. Bend down, Castle, and put your hands on my ass so I can get this leg on your shoulder. And then stand up, slowly—really slowly—and hold on to my waist until my leg is completely straight in the air."

She doesn't have to repeat the instructions. Within seconds she's in the most astonishing split he's ever seen, and with her heels on they're virtually eye-to-eye. "I think you know what comes next," she says into his half-open mouth.

"You, I bet."

"I said 'what,' not 'who,' but I won't be coming if you don't get moving."

He was right, though. She does come first, using some of the most colorful language he's ever heard—and hopes to hear again—and leaving bite marks on his shoulder that are war wounds he'll treasure. He can't believe how deeply he can go, or how powerfully she contracts around him, and when he spills into her he marvels, with the functioning area of his brain, not just at how flexible she is but how strong. Both of them are shaking when they collapse onto the sofa.

"What was that, Beckett?" he gasps, his head resting against her left breast. He can feel her heart racing.

"Lustful leg," she gasps in return. "Never done it before."

"Never?"

"Never. I was a lustful leg virgin until just now." She chuckles. "You were my first."

"You were mine, too. And I'm going to be lusting for this again very soon."

"You're usually the one who says this, Castle, but sorry, you'll have to wait. I haven't recovered my strength yet."

He looks down at her, his body sliding slickly over hers, and kisses her as powerfully as he can, given how spent they both are. He licks a drop of sweat from the hollow of her throat. "Best make-up sex in history."

"You know I'm still a little bit mad at you."

"Best angry sex in history, too, then."

To his astonishment, she flips him over. Sitting on his stomach, she braces her hands on his chest. "You know what will happen if you mention this to Espo, don't you?"

He feels a bit panicky. "Yes. Yes, yes."

"What exactly will I do, Castle?"

"Umm, what?"

"I'll become really, really, really inflexible."

"Okay, then, my lips are sealed."

"Not right now, though. I want them on me."