His mouth is already open when he walks into the bedroom but nothing comes out. He can't even remember what he was going to say, the words already erased from his mind by the sight in front of him.
Because she's curled around herself with her head at the wrong end of the bed. Her fingers are tracing over her stomach, writing a story across the delicately stretched skin.
"You gonna come in?" she whispers into the darkness, eyes opening to find his.
He drops the pad of paper on the bedside table before sitting at her hip. His fingers slide along the skin bared between the waistband of her sweatpants and where the t-shirt won't cover her stomach. "You doing okay?"
She hums, nodding into the comforter. "Fine. Just tired."
"He's not kicking," he says, smoothing his palm over her belly button.
"He's sleeping," she replies, putting her hand over his. "We're taking a nap."
So he scoots onto the bed behind her, an arm banding under her breasts so that his fingers can tickle at her side. "Love you," he murmurs into her neck.
She turns her head and brushes her lips over his jaw. "Still not naming him Indiana Jones."
"I've got a month to convince you."
"Not gonna happen," she sighs as she relaxes against him.
Just over a month, he holds the little body wrapped in a blanket. He's pacing the hospital room, eyes darting between the tiny fingers wrapped around his shirt to the woman on the bed who is watching him from behind sleepy eyes.
"Fine," she says quietly.
He turns, sitting on the edge of the bed, balancing the baby so that he can grab her fingers. "Yeah?"
"Okay, we're not naming our daughter Indiana."
Because their boy, the one they were so sure of being a boy, isn't. Instead, he's got the soft pink blanket-clad baby girl in the crook of his elbow. And he's happy. They're happy because she's healthy and beautiful and theirs.
"Diana."
She's clever. Diana is part of Indiana. God, he loves her. "Diana," he murmurs, running his finger over the baby's upcurved nose. The baby smacks her lips, eyes still squeezed shut. He moves closer to Beckett, pressing a gentle kiss to the corner of her mouth. "I love you."
"She's not wearing a hat and a whip on the way home," Beckett says with a grin.
About a day later, she's got Diana in her arms as he drives back to the apartment.
The girl is in a khaki onesie that is way too big on her tiny body under the blanket.
Castle is grinning on the entire ride home with his girls.