Disclaimer: I don't own Castle. The only profit being made is my own amusement (and hopefully yours).
September
The fact that they're both single again, coupled with the newfound knowledge that Castle is willing to work for a serious romance, leads Beckett to resume the flirting that she'd tried (and utterly failed) to suppress when Gina and Josh were still around.
She puts her hair into a bun and takes it out of the bun more than necessary, aware that he likes watching her twist her brown waves with her fingers and loves seeing it fall back over her shoulders. She adds an extra swing to her hips when she knows he's walking right behind her. And her favorite tease of all, whenever he mixes her a drink at the Old Haunt, she asks for a cherry and makes a tantalizing show out of eating it.
He makes more attempts than ever to invade her personal space, and for the first time, she isn't concerned about how much she enjoys it. His fingers brush hers—deliberately, she knows—as he's handing her a cup of coffee, causing a pleasurable ache to travel up her arm and below her ribs. He comes too close when he's peering over her shoulder to read a file, close enough that she can feel his breath on her neck, close enough that sometimes all she can think about is reaching for his tie and pulling his mouth to hers. One day, Demming gets onto the elevator as they're riding down to head to a crime scene. They'd been standing side by side, touching at the hips and shoulders; Demming stares at them but she doesn't move away.
A year ago, if anyone had asked her if she and Castle were together, her answer would have been an emphatic no.
Now, she knows, the only correct answer is not yet.