Disclaimer: All the characters belong to Andrew W. Marlowe, though they have found their own way into my heart.

Beckett let herself into the loft, thinking it was nice, for once, to get home early and be able to enjoy some time with Castle and…

The place was dark; all the lights were out except for one over the kitchen counter. It was really quiet, too.

"Rick?" she called out, her voice echoing off the walls in the open living room. No one answered. She started toward the study, dropping her bag and coat on the couch as she walked past it. Three feet from the threshold, though, a distant chuckle reached her ears and Kate spun around. It had come from upstairs. She climbed the steps and turned into the dark corridor. She could hear splashing of water coming from the bathroom down the hall. The door was cracked open, allowing a thin line of light to seep through and spill across the hall's floor. Beckett crossed the long corridor, pushed the door inwards and stuck her head inside. "Hi," she announced herself softly.

"Hey! Look who's here!" Castle exclaimed happily. He sat in the big bathtub with the two kids. The three of them were surrounded by white bubbles that reached and poured over the edge, dripping onto the floor. Their faces and heads were covered with foam as well, and Kate couldn't help but smile at the endearing picture.

"Momma!" the high-pitched voice of her son called, a big grin on his face. "I have a beard!"

"I can see that," Beckett chuckled.

The baby girl in Castle's arms flashed a dazzling grin in her mother's direction, showing four tiny white teeth, and started bouncing excitedly, flapping her chubby hands in the air. The foam on her head made her look like a shark. The detective walked over to them, cautious not to step with her high heels into the puddles of water covering the tiled floor. Crouching down beside the bathtub, she reached with her hand and wiped away the fake beard from the three-year-old boy's face. Then she leaned over the edge of the tub and kissed his red lips. The nine-month-old girl was next. Kate's face got all damp from the baby's wet cheeks. Last, Castle leaned forward, careful not to drop the girl in his arms, and pressed his lips to Kate's. Before she could pull away, his free hand moved to the back of her neck and held her in place. When he let her go, she was all covered in foam.

"Castle!" she complained, wiping her face and brushing white bubbles off her hair and clothes, but her son burst out laughing and she couldn't stay mad for long. The writer flashed his teeth in a triumphant grin, and Kate rolled her eyes in response. "Honey," she addressed her son. "Let me see your hands."

He quickly threw his arms up in the air, accidentally splashing water in her direction. "Oops," he shrugged innocently.

Beckett took his hands in hers and examined them. The skin of his little palms and fingers was very wrinkled. The detective's gaze flicked up to her husband's face. "How long have you been in here?" she demanded, frowning at him. She didn't give him the chance to answer, though, before she continued. "They look like 90-year-old kids."

"I'm not sure. Lost track of time..."

Still holding Rick's gaze with a disapproving look, Kate felt her son cradle her cheeks between his wet hands, gently turning her head so their eyes would meet, hazel looking into hazel.

"Play with us, mommy?" he asked softly. And as much as she tried, she couldn't deny that look anything. He may have inherited her eye colour, but he had the same pleading ability to put puppy-dog eyes like his father.

She pretended to ponder for a moment, puckering her lips to the side. The boy held her face close to his, waiting expectant and hopeful. "Very well…" she finally accepted. "Ten minutes."

She quickly stripped off and got into the tub —good thing it was big enough for the four of them. The boy immediately glided onto her lap and rested the back of his head against her shoulder. The baby girl extended her chubby arms toward her mother and Kate reached for her. In the blink of an eye, Castle found himself all alone at the one end of the bathtub.

"So, that's it? Mommy comes home and I'm abandoned?" He pretended to whimper sadly, hiding his face in his hands. A sudden chuckle escaped the boy's lips. Rick's head snapped up at once. "Did he just laugh?" he asked, faking astonishment and pointing a finger at his son.

"I think he just did," Kate answered neutral, trying to keep her inner grin from seeping onto her face.

Castle leaned forward and fixed an intense gaze on his son's face. "Did you just laugh at your father's misery?" The boy shook his head fervently, his hands clasped over his mouth and his eyes crinkling with the smile he was trying to hide. "I think you know what that means, don't you?" Castle said in a warning tone. In one quick motion, he scooped the boy up in his arms, balanced him mid air, and loudly blew a raspberry on his belly.

"No, daddy!" the kid squealed and laughed. His legs kicked and splashed water and foam everywhere, soaking everyone, while his father blew a second and a third raspberry on his tummy. "STOP!" he shrieked, panting.

The baby started laughing, too, and soon turned red.

"Castle, enough," Kate chuckled. "They'll choke."

The writer stopped the torturing game and settled his son in his lap. Both kids were gasping for air, their eyes sparkling with happy tears. A minute later, when their breathing had returned to normal, the boy's mouth opened into a big yawn and his sister joined him involuntarily.

"Okay. Bedtime," Beckett announced. Handing the baby over to Castle, she stood up and stepped out of the tub. She pulled on a bathrobe, grabbed a couple of towels from the cabinet, and wrapped one around the girl Castle was holding out to her again. He got out of the bath as well, put a towel around his waist and pulled his son out of the water.

"Why don't you get them into bed, honey?" Rick said to Kate, handing the boy to her. "I'll clean this mess up."

"Sure."

After Castle dropped two kisses on the children's foreheads, murmuring a "Good night" to them, Kate headed to the baby girl's nursery, carrying both kids in her arms. She lowered the three-year-old down to the floor, sat the baby on the changing table, and started drying her skin gently with the towel.

"Can I sleep with her, mommy?" the boy asked. Kate sighed. He'd been asking the same for the past three days. The detective lifted the baby's legs and put on a diaper.

"No. I'm sorry, love," she answered, getting her daughter in her jammies. "She's too small."

"I won't hurt her," he whined, his voice slightly quivery.

Beckett turned her head and looked down at her son. "Sweetie, when you're asleep, you don't know what you do, and you could roll over her by accident," she explained to him in a gentle tone. His eyes teared and he started to cry anyway. Kate picked up the baby, walked over to the crib and laid her down. Sobbing, her son followed, dragging the big towel he was wrapped in over the floor. The detective kissed the baby's forehead and pulled the blanket tightly around her small body. Her lids were already half-closed, hiding her big blue eyes.

"Pl—ease... I—I won't— hurt her," the boy stuttered between sobs. "I love her."

Kate knelt down at his height and looked at him. His eyes were red, leaking big tears that rolled down his cheeks. Without saying a word, she opened her arms and the boy sank into them. She hugged him and rose to her feet. He wrapped his arms around her neck, letting his head fall onto her shoulder. Beckett held him tight against her chest, rubbing his back to soothe him; he had the hiccups from so much crying. She crossed the hall, walking into her son's bedroom, and sat on his bed, placing him between her legs. He started to shiver and she noticed he could barely stand on his feet; he was exhausted. Kate rubbed him with the towel, dried his brown hair, and wiped away the remaining tears. Then she put on his PJ's, sat him on her lap and rocked him gently from side to side until he calmed down.

"Can we see Alexis tomorrow?" he whispered when he was tucked in under the covers.

"Well… Tomorrow is Saturday, so I think we could call her to see if she's free," she murmured softly.

He nodded, his eyelids growing heavier with sleep. She brushed back the long locks of hair from his forehead and kissed his cheek.

"Sweet dreams, my love." She wrapped the sheets tight around his body and walked out, leaving the door ajar.

There was still light coming from the bathroom. She went in to check what was taking Castle so long. When she stepped inside, she saw why. The room was dully lit by dozens of candles, scattered on the counter and shelves. The smell of lavender floated in the muggy air, enveloping her in a dense, sweet cloud. Her husband was in the refilled tub again, waiting for her. A sly smile curved Kate's lips as she slipped out of her robe, letting it fall down to the floor. Castle's eyes roamed hungrily over her body. She slowly approached the bathtub, got into the water and settled between his legs, leaning her back against his chest. His arms wrapped around her, and she nestled her head into the crook of his shoulder.

"What was that all about?" he asked in a soft voice, pushing her hair back from her temple.

"Your son, throwing a tantrum," she answered, amusement tinging her tone. "He wanted to sleep in the crib with the baby."

Castle chuckled once. "Aren't we lucky," he murmured in her ear.

Beckett tilted her head and looked up at him from the corner of her eye. "Yes, we are." And she pressed her lips to his jaw.

Kate woke up the next day to soft morning light streaming in through the half-drawn curtains. She propped herself up on one elbow, glanced at the alarm clock with tired eyes and frowned. Something felt off, out of place. It was way past the time when one or both kids were up, filling the house with their screams or laughter. The detective grabbed the baby phone from the nightstand; it was on and working just fine. But when she took a closer look at the small monitor screen, she saw something odd inside the baby's crib. Kicking the sheets aside, she rushed upstairs. When she reached the nursery, though, she stopped short under the threshold, her hand coming up to rest on her racing heart. Quietly, Kate walked over to the crib. Her son was lying in the small bed with his baby sister. They were cutely huddled up, facing each other, and the boy had an arm draped protectively over his sister's waist. A smile spread on Kate's face.

She reached for the baby phone on the shelf near the crib and brought it up to her mouth. "Castle," she whispered softly, trying not to wake the children. "Castle... You gotta come up see this."

"...What?" came his husky voice a moment later.

"Get upstairs. You've got to see this," she repeated, then added, "Bring your phone."

A minute later, the writer appeared at the doorway, wearing a sweatshirt over his tee and flannel pajama bottoms, his hair sleep rumpled, and his eyes puffy. "What is it?" he mumbled, rubbing his face and shuffling his feet to her side. She pointed down and his gaze followed. "Oh..."

Beckett nudged Castle's side and whispered, "Take a picture."

He lifted the phone and snapped a couple of shots.

"You know what this means, don't you?" he chuckled near her ear. She looked up at him with an arched brow. He continued, "He's gonna sneak inside her crib every night."

Hope you liked it! This short piece just popped into my head, and I had to write it down!

Thank you so much for reading!