Beckett and Castle walked hand-in-hand to the OB/GYN, Alexis and Martha trailing behind. The Castles were all chattering excitedly, but Beckett was quiet, savoring the last few moments of unknown.

She felt a squeeze of her hand. "You okay?" Castle asked.

"I'm fine," she replied, a gentle smile flowing easily from her to him. "I'm just a little nervous is all."

Martha exclaimed from behind them. "Oh! Not to worry, dear, boy or girl doesn't matter as long as Boo is healthy."

Chuckling, she heard Alexis squeal and clap quietly behind her and she looked back to smile warmly at the young woman. "It's gonna be fine," Castle soothed.

"I suppose I'm just anxious to finally be able to put a gender with the personality I've come to know," she explained further.

Alexis scrunched up her nose behind the expectant couple. "Boo already has a personality?" Her question was so sincere, Beckett stopped cold in her tracks causing the rest to jerk to a halt.

Swinging around, Beckett took both Alexis's hands in her own and gave her the most sincere look she could muster as she apologized. "Oh, Alexis, I'm so sorry!" When the red-head looked even more confused, she continued. "Boo absolutely has a personality," she said, looping her arm through Alexis's as they continued walking toward their destination. "I think Boo's a little sassy. He love spicy food, but not too often or he won't stop kicking me. He likes it when I lay on my left side, I think so he can see hear his daddy's bedtime stories better."

Rick's face softened as he discreetly listened to his wife tell his daughter about their child. "She can't stand sitting still for too long; she gets restless and it feels like she does flips in my belly." Turning, Rick sees that Alexis is absolutely enthralled at Kate's story, drinking in every last word, her free hand resting on Kate's belly, searching for the baby inside.

Seeing the younger woman's excitement, Kate continues. "Boo loves it when we sing to him. She gets really still and usually falls asleep."

"You can tell when Boo's asleep?" Alexis asked eagerly.

Kate nodded. "Sometimes. Like, in the morning if I have to wake up early, Boo does not wake up with me. She doesn't move until she gets her first sip of coffee; I guess he doesn't know that my coffee is always decaf now." Alexis chuckles beside her.

Tentatively, Alexis plays with a strand of her hair and asks, "Kate, would you mind if I sang to Boo tonight? After all, he's my brother or she's my sister, and I want my voice to be known, too."

Beckett found Alexis's hand and squeezed. "Of course, Alexis. Any time you want."

"Thanks," Alexis whispered.

They finally made it to the doctor's office and into the waiting room. Kate sat between Castle, who had a protective arm around Beckett, and Alexis, who was studying Kate's stomach looking for any signs from her sibling. A bump rolled across the top of Beckett's belly and Alexis jumped, pointing at the spot that was now gone.

"Aw, that was Baby Boo!" she said enthusiastically. "Come back, little one. Sissy wants to play with you."

Everyone's faces lit up as Boo made another appearance in the form of a foot near Alexis on Beckett's right side. Alexis squeaked with joy. "Thank you, Little Bit." She paused for a moment before she leaned down, her lips hovering over Beckett's belly, and whispered, "I love you."

Alexis's Little Bit nearly kicked her nose.

XXXXXXXXXX

The wait isn't much longer. About two minutes later, the nurse pokes her head through the door and calls Beckett's name. As she and Castle begin toward the door, Beckett stops short and looks back to the two read-headed women. "Come on," she says with a smile. "Let's go see if Boo is a boy or a girl so we can finally get the kid a damn name."

A little shocked, Alexis and Martha stand and reverently follow the rest into the exam room. Beckett lies on the table and Castle stands by her head. Martha and Alexis take up the two visitor chairs and everyone waits for the ultrasound technician.

"Pink or blue," Alexis says softly, still in awe.

Kate chuckles and replies, "Neither. Boo can decide what colors to love, boy or girl. I'm going to paint the room something neutral so if it's a he and he loves pink, that's fine."

Turning to face her soon-to-be-stepdaughter, she just sees her nod and accept the decision. "Makes sense," she heard the girl utter quietly.

As the technician entered the room and prepared the machine, Castle's hand squeezed Beckett's just a little tighter. "You ready?" he asked.

"Definitely," she whispered, eyes shut tight, waiting to hear Boo's tiny heartbeat fill up the room. When it did, a slow, luxurious smile spread across her whole being. She felt the wand being wiggled around and pressed onto her belly until it stilled and Castle leaned down.

His voice was a whisper in her ear that filled her up with such hope, anticipation, anxiety, and fear all at once. "Open your eyes and meet your son."

XXXXXXXXXX

IT'S A BOY was written on the screen next to a little bit of gray amidst the black that was too small to be a hand, but too big to be a finger.

"And he's sucking his thumb!" Alexis was ecstatic. She was holding onto Martha's hand (Martha, who—for once—was stunned into silence), and bouncing her knees. "My Little Bit's a boy!"

While all this was happening, silent tears rolled down Beckett's cheeks; she didn't care. They slid gracefully down as she looked up at Castle, whose emotion mirrored her own as he kissed her forehead, her temple, whispered softly, "I love you, Kate. Thank you for this." His eyes glanced at the screen: their son.

"Oh, Castle, I love you so much."

The technician congratulated them, then slipped out the door to give the family some privacy. Alexis leaned over Kate's belly while Martha went to her head, hugging her as best she could while Beckett was mostly lying down. "I'm so happy for you both," she said, placing a hand on her son's cheek.

When Martha tapped Alexis's shoulder and nodded toward the door, Alexis smiled and kissed Beckett's belly before hugging her step-mom and exiting the room grinning from ear-to-ear.

Sitting up, Beckett held her arms out for Castle, who willingly went. After a long moment, he pulled back and said, "This is it, Kate. No going back." He didn't mean time travel and she knew that, but she looked at him so seriously and replied, "Never."

The happy little family walked home, chattering excitedly the whole way about names, who he'll look like, what he'll act like, etc.

While names were being tossed around, Alexis spoke up. "You guys call him whatever you want. To me, he'll always be my Little Bit." Kate wrapped her arm around the girl's shoulders and squeezed tight.

"Sounds perfect."