Beckett's foot was bouncing beneath her desk as she stared at the pile of paperwork in front of her. She hated desk duty. Unfortunately, that was where she would be spending the rest of her pregnancy, since their little Nana had become big enough to just be a baby now.

"Kate!" Castle interrupted her thought process. "You're driving me crazy with your bouncing leg. What is wrong?"

With a sigh, Beckett looked up at her lover. "I just hate sitting here. I feel useless."

Castle smiled at her and said. "I know, Beckett, but it's for Baby Boo. We can't let anything happen to her."

Beckett's eyes rolled. "Or him," she said as she leaned back in her chair. "And I know. I went on desk duty a little earlier than normal because I didn't want anything to happen to Boo." She placed her hands protectively over her stomach. "It's the same reason, I," she glanced around to make sure no one was listening, "don't travel anymore." She placed extra emphasis on the 'travel' so he would understand she meant more than going from New York to Virginia.

Five o'clock came around and Castle helped Beckett into her jacket, then rode the elevator down with her. They got in his car and went to his place, going about their relatively new routine as an almost-family. Once dinner had been eaten and cleaned up, the two (or three, she supposed) of them sat on the couch watching Netflix and snuggling. Castle rubbed Beckett's belly and explained the plot of the movie to little Boo.

Before long, he paused the movie and sat up to face Beckett. "Can I ask you something," he began hesitantly.

"Sure," Beckett replied, "always."

Castle was completely calm and collected, so Beckett was only slightly nervous at his tone. "Can you travel forward in time or just backwards?"

Breathing a sigh of relief, Beckett chuckled. "Uh, no, I can't go forward in time, only back."

His face scrunched up and Beckett laughed. "But why?" Castle whined. "Going forward would be so cool. We could spy on Boo!"

"Babe, even if I could go forward in time, I wouldn't spy on our kid. That's weird and I wanna be surprised. I want to watch little Boo grow up and see what he or she becomes."

Considering her for a moment, he finally responded, "That's fair, I guess." She looked at him, waiting for his face to go back to normal, but he still looked confused.

She rested her hand on his cheek. "Castle, what is it? What else is on your mind?"

He took a deep breath before once again facing her and began. "Why don't you really go back in time anymore?" When he saw her brow furrow, he continued. "If it hadn't been for me asking you not to, would you still have gone back in time to try to get us right?"

Beckett looked a little horrified, but quickly collected herself when she saw his slight panic. "Castle, no! I wouldn't have gone back because I still would have gotten pregnant and I would never, ever risk our baby like that."

"You keep saying that, but I'm not sure I understand what you mean," Castle replied. When Beckett didn't reply, but looked at him quizzically, he added on. "What do you mean when you say you wouldn't risk our baby?"

Straightening up, she smiled at him. "First of all, you know how much I love you. I've tried to show you over the past several months and I try to tell you as often as I can." He smiled at her and placed his hand on her knee.

"I know. I love you, too."

Beckett smiled appreciatively, but continued on. "Well think about how much you love Alexis." When he grinned stupidly, pride beaming from his eyes, she pressed on. "That is how much I love Baby Boo. My mom once told me a story about some great-great-great- relative who got pregnant. Right after she gave birth, her younger sister died. She was heartbroken, had almost raised this sister, so she went back to try and change it, try to save her sister, but it backfired."

"How?" Castle asked, completely enthralled in her story.

"When she went back to try to save her sister, her pregnancy felt different; the baby in her belly was different. She just knew something was off." Castle looked thoroughly confused, so she tried to explain. "She panicked and so she went back to her present, but instead of a little girl, she had a boy who was nothing like her baby."

"Why was it different, though?" Castle asked earnestly.

Beckett smiled a soft smile at him. "I have no idea, but she had to choose. She could either save her sister and raise the little boy who didn't feel like hers, or keep her baby girl and let her sister die."

"What did she do?" Beckett took a moment for a dramatic pause.

"Her daughter's name was Ava, after her aunt Avaline." Beckett smiled at Castle. "So that is one of the reasons I have given up my ability. I love Boo, Castle. I don't want another baby, I want Boo, Nana, Peanut, and whatever we decide its name is. I don't want to risk ending up with some baby that isn't this one and I don't want to live my life without you. I don't want to travel back because I nothing I have back then is better than what I have now."

Castle's face melted into a mask of tenderness as he pulled his love into his arms, holding her close, kissing her hair. "I love you, Katherine Beckett, and I can't wait to meet our baby, and I can't wait to spend the rest of my life showing you how much I love you."

Beckett only hummed in response, breathing him in and basking in his love for her.

Moments later, he lifted his head from hers and said, "I think it's about time we found out whether our Boo is a he-Boo or a she-Boo, don't you?"

Beaming up at him, Beckett replied, "I think so."