Kate's cell phone vibrates and rings, vibrates and rings until one slender arm emerges from beneath the blankets and grabs it. She squints at the display. Esposito calling her at a quarter to five in the morning? Her stomach rolls with dread. This can only mean another pregnant woman is dead.

"Yeah," Kate says. Her voice is clogged with sleep and a headache, born of too much stress, is blooming behind her eyes.

"We got another one," Esposito says. "This one's worse."

Kate throws the blankets aside and slides out of bed, reaching for a pair of jeans.

"What do you mean, worse? How can it be worse?"

Esposito doesn't answer right away. She hears sirens and raised voices, the sounds of an active crime scene. "The baby is dead." He pauses. "The bastard killed it."

Castle is already at the crime scene when Kate arrives. She stops beside him, her hair pulled up into a messy bun and a scarf wrapped around her neck. It's snowing and windy and her face is already red with the cold. He doesn't want her to see what she has to see; the sight of a woman, throat slashed, her pregnant belly sliced open and the fetus lying in a pool of bloody snow. So much blood. He wishes he could take her away from here and protect her from the ugliness of the world. But this is Detective Kate Beckett, and she's here to do her job.

"It's bad," he says to her. She nods.

"Ryan and Esposito?"

"Talking with the restaurant workers who found the body."

She takes a deep breath, squares her shoulders and walks down the alley towards the bright lights, the uniform police, the area of death sectioned off by yellow police tape. She sees the spreading pool of blood first. Then she sees a shoe and a leg and finally the ugly scene is before her. Kate is shocked by the sight of the lifeless fetus sprawled in the snow, the umbilical cord still stretched to the mother's body. Her stomach twists and she feels bile rise in her throat. The woman's throat is cut so deeply that the head is nearly detached. Her eyes are open and staring sightlessly at Kate.

"Oh, fuck," Kate whispers to herself. "Fuck fuck fuck." She doesn't want to do this anymore. She wants to go back to bed and forget she saw this, forget there are people in the world capable of deeds this evil. She wants to be a child again, innocent and happy. Kate doesn't see Lanie come up behind her and jumps when she hears her voice.

"Hi, girl. Not how you want to start your day."

"No." Kate swallows. "No, it's not. COD?" Although it's fairly apparent what caused their deaths, Kate needs her friend's official ME theory.

Lanie kneels near the woman's body. "Well, the woman's throat was slashed so deep that she was nearly decapitated. The baby," Lanie hesitates. "The baby was cut from the womb and battered…I'd say slammed against the concrete sidewalk."

"Jesus," Ryan says. He crosses himself quickly, barely aware of his motion. "Who the hell does something like that?"

"That's what we have to find out," Kate says crisply, trying to exude the aura of a lead detective who knows exactly what to do. "Lanie, do you have a time of death?"

"Well, it's a little difficult to narrow down a time due to this cold weather, but right now my rough estimate is between 9 p.m. and 2 a.m. I'll be able to give you a better report once I've finished the autopsy."

"I can help you with that," says Esposito. He is walking towards them flipping through his notepad. "The restaurant here closes at 9 p.m. on Sunday. I talked to Gus and Lennie who took out the trash last night around 9:30. She wasn't here then."

Kate nods. "We have an id on the vic?"

"No. No purse, cell phone, nothing," Ryan answers.

"Okay, then. Let's canvas the area, see if anyone knows anything. I'll get a few uniforms to start searching nearby dumpsters and trash cans. We also need to check missing persons reports. Someone is worried about her."

Ryan and Esposito and a group of uniform cops scatter to follow her orders. Kate walks back to where Castle is now standing with two hot cups of coffee. Wordlessly, he hands a steaming Styrofoam cup to her.

"Thanks." She closes her eyes and takes a long gulp, not caring that the coffee is scalding hot. Right now she welcomes the pain. It reminds her that no matter how numb she feels, she is still alive.

It's 10:30 at night when Castle's phone beeps at him. He is half asleep in his study, his head nodding over his laptop. It's been two days since the fourth body was found and there haven't been many leads. The woman's name was Tina Yolanda and her husband collapsed on the couch in disbelief when Kate notified him that his wife was the latest victim of the "mommy murderer." Castle had been with her and saw how close Kate had come to losing control of herself. When they got back to her car, she brushed aside the tears on her face and turned to glare at Castle as if daring him to comfort her. He didn't. But as the next 48 hours yielded very little information regarding the killer, Kate grew increasingly short-tempered and frustrated. Now his phone is ringing and it's Esposito.

"What's up?" Castle says, yawning and rubbing his eyes. He's working on an outline for the next Nikki Heat novel and he didn't get very far before falling asleep.

"It's Beckett. She's at the precinct staring at the murder board and muttering to herself."

"What? I thought we all left at seven."

"We did. But I couldn't find my cell phone and remembered I'd left it on my desk. When I went back to get it just now, she was there." Esposito pauses. "Bro, she doesn't look good."

"Oh, shit." Castle stands up, stretches. "Did you tell her to go home?"

Esposito snorts. "Yeah, man, of course I did. You know Beckett. No one can tell her anything. I'm worried about her. She looks like hell and she's gonna drop from exhaustion if she doesn't get some sleep. She's not helping herself or the case by obsessing over it."

"So you want me to go get her," Castle guesses. He's already looking for his wallet and thinking he'll call his car service rather than get a taxi.

"Yeah. Our girl listens to two people: you and Montgomery. The captain's not around anymore, so that leaves you."

"Shit," Castle says again. "Okay, I'm going."

"Good luck," Esposito says and hangs up.

Thirty minutes later Castle strides into the precinct. In his haste, he forgot to change out of his pajama bottoms—sleep pants given to him by Alexis a few years ago. The words "#1 Dad!" and "My Dad's Great!" are printed in red and blue on a background of bright yellow flannel. They're not exactly his style, but they are warm and comfortable and Alexis gave them to him. He just wishes he hadn't been wearing them tonight. He doesn't see Kate right away because most of the lights in the room are off, but then he notices a form pacing back and forth in front of the murder boards. Usually just one board, for this case two others have been brought over and lined up. Lots of victims, no suspects.

He stops when he's a few steps away from her. She is so immersed in her own head she does not hear him approach and he doesn't want to startle her. Her normally beautiful wavy chestnut hair looks dull and flat. Her blouse is sloppily tucked into her jeans. She's facing the board with the most recent victim's information, staring at the crime scene photos as if she could get answers by sheer force of will.

"Kate," he says quietly. She doesn't respond.

"Kate," he says more loudly. She gasps and spins toward him.

"What the fuck, Castle, you scared the shit out of me," she snaps at him. "What are you doing here, anyway?"

"One could ask you the same question," he says, ignoring her tone. Esposito is right, she doesn't look good. There are dark circles under her eyes and her face is very pale.

"Well," Kate replies, "one could but one should just mind his own business." She turns back to the board and tries to ignore him. Castle is tired and not in the mood for her normal "I'm Kate the invincible" routine.

"Would you stop this bullshit?" He lets some of the anger and worry he's feeling into his voice. "It's after eleven. You've been here since at least seven this morning. You're going on maybe, what, eight hours of sleep in two days? Kate, you need to stop. You're wearing yourself out." Kate doesn't acknowledge his words, but he knows she's angry by the stiffness in her shoulders and her clenched fists.

Castle ignores her lack of response and continues. "How will it help the case if you collapse from exhaustion? And low blood sugar because I don't think you're eating either. Kate," Castle puts his hands on shoulders and turns her to face him. He's disturbed by how thin she feels. "You aren't helping these women and their families by running yourself ragged. If you want to help them get justice you need to go home and sleep. And eat a decent meal." He looks into her eyes, expecting her to pull away from him. Instead, he is amazed to see tears fill her eyes and fall unchecked down her face.

"I've tried, Rick," she whispers. "I go home at night and I make dinner—not even leftover Chinese take-out, I swear—and I can't eat. Food makes me nauseous. How can I eat when these women are being murdered? How can I sleep? They are depending on me to find their killer. Their families want justice. But I'm failing them. I don't have any evidence, any leads. How dare I enjoy a good night's rest when every moment that bastard is free another woman's life—and her baby—is at risk?" She's looking up at Castle, pleading with him to understand. His heart twists. He's never loved her more than he does now and he's never wanted to wrap her in his arms and protect her from the world the way he does now.

"Oh, Kate, honey," he says. He pulls her gently towards him and wraps his arms around her shaking body and holds her closely. At first, she resists, but then something breaks inside her and her arms go around him, pulling him even closer to her.

"It's going to be alright, Kate," he murmurs to her, pressing his lips to the top of her head. "I swear I'll make everything alright."

Kate hears him speaking but doesn't listen to the words. His voice is as soothing to her nerves as golden honey with a shot of fine whiskey. It feels so good to be held by him, his strong arms wrapped around her, her head on his chest. She's stopped crying but doesn't want to leave his arms yet. His black sweater is soft on her cheek and whatever cologne he is wearing—maybe it's just Eau de Richard Castle—is making her weak in the knees. Of course, that could be due to her not having eaten since her turkey sandwich hours ago. Finally she sighs and lifts her head, meeting his concerned gaze.

"Better?"

She tries to smile but instead feels herself tear up again. "Damn it, Rick. Stop being so nice to me."

"Never," Castle says and bends his head towards her, his lips brushing her cheek. "I definitely think," he kisses her other cheek, "that it's my job to be nice to you." Now he's looking at her, those blue eyes dark and intent on her. She stares back at him, wondering what it would be like to lose herself in that electric blue gaze while they make love. Just as soon as that thought crosses her mind she blushes and a spark jumps from her to him and she knows she should look away, knows he can guess what she is thinking, but she can't, she's trapped, and his hands tighten on her shoulders as he kisses her, his mouth painfully hard on hers. Kate sighs, reveling in the sensation of being kissed by him again. She slides her hands under his black sweater to explore his muscled back, moaning when his tongue slips into her mouth. Her traitorous body responds to him shamelessly. When he gently bites her left ear and brushes his scruff against her neck, she gasps. Her hands stroke his back then dip beneath the waist of the sleep pants to grasp his firm round butt. He pulls her blouse loose from her jeans and his warm hands slide up her stomach and stop at the edge of her bra. His thumbs stroke her breasts until her nipples are hard and she hears herself saying, "Rick…Rick, please" in a voice she doesn't recognize as her own.

Castle isn't sure if she is begging him to stop or continue, but he doesn't think it matters as he isn't in control anymore. Years—years!—of wanting this woman, magnified by the passionate love he feels for her, have made this moment inevitable. The sensation of touching her and tasting her and feeling her hands on his body has destroyed his plan to take it slowly with her. His flannel pajama bottoms are in no way disguising how aroused he is and her moaning his name fuels his desire. He reclaims her mouth in another deep kiss and pulls her leg up to his waist and holds it there so he can wedge himself more firmly against her. Kate gasps and rolls her hips against him, feeling a spasm of pleasure as she rubs against his erection. He's moaning too, whispering her name into her ear, his other hand gripping her bottom and guiding her movements. She doesn't care anymore about where they are or trying to hide her feelings for him. She cares only about how good this feels.

Which is when she loses her balance and they both fall backwards, crashing into one of the murder boards. They lie there for a moment, stunned by the fall and still in a sexual stupor. Finally, reluctantly, Kate untangles her legs from his and pulls away from him. They are both breathing hard and Kate's face is flushed. Her blouse is unbuttoned—when did that happen?—and she can't look at Castle. He curses quietly and stands up, then offers his hand to Kate.

She lets him pull her up, trying not to look at his face or below his waist where the fabric of his sleep pants is still pulled taunt against what Kate must admit is an impressive erection. She's surprised he hasn't bragged more. She focuses her eyes somewhere mid-chest, which seems fairly safe as long as she doesn't remember how sexy the muscles of his chest and biceps felt when he held her. Her face is red again. She hears Castle clear his throat.

"I hope that wasn't a mistake. But I think that you think that it was."

Kate chances looking at his face. His lips are swollen from their kissing. His eyes are very blue and her caressing hands left his normally well-groomed hair rumpled and chaotic.

She chooses her words carefully. "I would say…bad timing. And location."

"Ah." He pauses. "Would coming back to my loft take care of those problems?"

His loft. She's never seen his bedroom, but she can guess that he probably has a very large, comfortable bed. Kate wants to finish what they've started—does she ever—but sanity is returning. And with sanity comes the memory of the murdered women and her stalled investigation. Not to mention that if she does stay the night with him, she'll have to acknowledge her feelings for him. She isn't ready to do that yet. Or face his mother and daughter the next morning. Oh, no, no. She is not ready for that yet. Kate shakes her head.

Castle sighs. Damn. Of course, seducing her in the precinct was probably the stupidest thing he could have done, but when she's that close to him…. He feels his pulse speed up and his blood is throbbing again. Castle closes his eyes and begins conjugating sentences in his head. The dog jumps over the log…dog is the subject…over is the preposition…log is the object of the preposition…speaking of log, I have to stop thinking about this because I cannot walk around with a giant hard-on….

When he opens his eyes Kate is looking at him oddly, her head tilted to one side. Her blouse is buttoned unevenly—the gap is right over her stomach, a stomach with silken, smooth skin, a stomach he stroked while she moaned his name and—

"I have a car waiting outside. Please allow me to take you home," he growls at her. Really, he has to either get away from her or ravish her. His self-control is at a low point right now. Kate seems to understand this because she frowns at him.

"Please allow me to take you to your apartment so you can sleep. Alone," Castle adds.

"Okay." She looks down at the murder board still laying on the floor. "Help me with this." They pull it upright. The pictures are askew and the magic marker writing is blurred in some places, but it's otherwise unharmed.

"Glad we didn't break it," Castle says, then laughs. "Can you imagine what Gates would say?"

Kate flashes him a look.

"What, too soon?"

In the car, he sits way over on the driver's side and she jams herself against the opposite door, each silently daring the other to breach the emptiness of the black leather seat between them. Ironically, not touching seems to make them even more aware of each other's presence, so much so that Kate can hear him breathing, feel his heart beating and has to sit on her hands to stop her fingers from tip-toeing over to his thigh. The driver, who probably thinks they are both insane, keeps looking in the rearview mirror and chuckling to himself. When the Lincoln pulls up in front of Kate's apartment building, she gets out quickly…then hesitates before walking around the car to Castle's side. He lowers the window.

"Thank you," she says. "For coming to get me and for…well, thank you." His face is scratchy beneath her hand and Kate kisses his mouth softly. She pulls away from him and grins. "By the way, I love your flannel pjs. So sexy." His face relaxes into a smile and she hears his laughter as she walks away from the car.