It took all of about ten seconds.

She had been going over the current case with Ryan and Esposito before they started their interrogation of a suspect. She had another lead to go and follow up, but she was waiting for Castle to come back with her coffee. It would be her third one of the morning, but the unhealthy caffeine intake didn't bother her. How long he was taking to get back was.

She was talking about the guy in their interrogation room when the elevator doors pinged open, and she turned her head ever so slightly towards them to see who it was, already knowing the answer, but just wanting to make sure.

Except this morning it was different. Today, she was noticing something more. She didn't turn back to the boys like she normally did and pretend she hadn't seen him coming. She kept her eyes on him as he made his way across the bullpen. Today, for some reason she couldn't quite put her finger on, she was seeing him in a whole new light.

She secretly liked the way his neck muscles moved as he turned to smile at all the officers and detectives he passed on his way over. She liked the way the corners of his eyes pinched up when he did smile, and she liked the way his smile lit up the space around him.

She liked the way that shirt looked on him, smart enough to be appropriate to wear to the work place, and clever enough for her mind to wander just a little bit and wonder what it would be like to undo that next top button. She liked the way his arms tensed slightly the way he held a coffee in each hand, and the way his jacket was slung over one arm, rather than the way he usually wore it.

She liked the way his hips swayed ever so slightly as he walked, and she liked how he slowed the tiniest bit as he passed her vacant desk. Dragging her eyes back up to his face, she saw the twinkle in his eye as they looked at each other, smiling, and she liked how his lips were full, and his little fanboy grin.

She marvelled at how he managed to make her heart beat a million times a minute whenever he was around, and she marvelled at how she managed to keep her cool whenever he was. She liked the adrenaline rush she felt whenever he was standing next to her, or behind her, or sitting across from her at her desk. She liked how he was sweet, and how he was always getting her meaningful little presents that she thought he wouldn't be thoughtful enough to get.

She liked the fact that as each day went past, he was slowly changing her mind about him. Her view of him now was very different from the first day they'd met, when he'd been the arrogant, charming playboy. She liked how he'd been making her rethink her first impression on the third day, when he'd left the precinct with his mother and daughter. It had started changing when he brought her coffee every morning, and when his ridiculous theories started making her think about what else could have happened.

She liked the fact that in the short space between the elevator doors and where she was standing, he could make her think about all of this.

And it was in that moment that she knew. Rick Castle was the man she was going to spend the rest of her life with.

"Hey," he said, a twinkle in his eye, reaching out his left hand and passing over the coffee.

She reached for it, her fingers momentarily closing around his before he let go, and she stared back into his eyes.

"Hey," she said back, smiling, a similar twinkle in her eyes as she realised that this was the man that she was in love with. Still smiling, she raised the styrofoam to her mouth, so breakable yet so full of warmth.

Just like her heart. Just like his.