He watched her from the shadows.
It was Monday evening and the twelfth precinct was virtually deserted, but there she stood, just like she had every Monday night, silhouetted against the bright white of the murder board - the office lighting having vanished several hours before, along with everyone else. He was giddy. He couldn't pinpoint it exactly, but something about their weekly crossing of paths filled him with a sense of wonder and purpose that made the rest of the week seem dreary in comparison. Maybe it was the way she stood sentinel, protecting the city well into the dark of the night. Maybe it was the utter absorption in the task at hand - the way she'd scrunch her nose or furrow her brow while thinking, mouthing something to herself before hurriedly rearranging pictures. Maybe it was just nice to know that somebody else, anybody else, existed at this time of day.
Then again, he thought, maybe it was the way she bent over in those very tight jeans to write something low on the board, and he tilted his head to the side for a moment to enjoy the view.
"Staring is creepy," said a hard and tired voice a few minutes later. He snapped to attention. Oops! He had been staring. She had turned around to peer over her shoulder - when had that happened?! - and her dark eyes bored into him from across the room. She narrowed them at him, expecting something.
"I'm ...sorry?" he tried. She turned back to the board, with the barest hint of a smirk and continued writing.
"Either you're very devoted to cleaning that one square foot of hardwood over there, or you see something that interests you over here. Which is it?" she asked, tossing him another look.
"I -" He looked down helplessly at the mop in his hands, which he suspected hadn't moved in a while.
"So what do you think? See anything interesting?"
Yes, he had seen something very interesting, but that couldn't possibly be what she was referring to. His brain, caught off guard, had completely discontinued regular functioning, but his traitorous feet had begun to move across the bullpen towards her, drawn towards her, abandoning his mop and cart, and the better part of his self-preservation instincts.
When he reached her, she stood and turned toward him, staring at him intently and appraisingly in a way that suddenly had him nervous, and he thought momentarily of the poor criminals who must have sat across from her in interrogation. He immediately wanted to confess his guilt for any number of things and he hadn't done anything wrong.
"So what do you think, Castle?" she asked after a moment, tilting her head towards the board.
Castle was not his name. It was, however, the name on his coveralls, a remnant of a bygone era when the city had enough money to spring for things like customized embroidery on its work uniforms. His name - the name on the ID badge hanging from a lanyard around his neck and currently tucked into the neck of his t-shirt - was Richard Rodgers. She said the name with such an air of amusement, however, that he didn't have the heart to correct her. For her, he could be 'Castle,' ...or anything else she wanted.
"I'm sorry, I didn't catch your name?" he fished.
"Detective Kate Beckett. Homicide."
"Well, Detective Kate Beckett-Homicide, I think I'm glad to be right where I am and not up on that board." He smiled what he hoped was an endearing smile at her, and she rolled her eyes at him briefly before turning back to ponder the board, but he thought that maybe, just maybe there was a hint of a smile. He couldn't be sure because it came and went so quickly, but it made his heart quicken a little. That was the story of how he met Kate Beckett, and that is how he became Castle.
Later, much later, when he came home, bone-tired, coated with a thick layer of grime from a hard night's work, he wrote what happened down. He didn't know why. Really, he would have been much better served falling face-first into his mattress, but it had been a long time since he had written anything, and this was the first event in a while that he wanted to be able to come back to.
There are two kinds of folks who lurk around in the dark watching people, he wrote, psychopaths and janitors. I'm the kind that pays better. (He made a face at that last part, not entirely certain it was true.) Truth is, they're the lucky ones, because she's chasing them, and I can only watch. He wrote for a while longer, describing Detective Kate Beckett-Homicide in detail, though leaving out the part about the very tight jeans and the bending over, and saved the file as 'Castle.'