He didn't know when it happened, but somehow it had happened: Castle had grown accustomed to the hive of activity that was the 64th precinct homicide bullpen. Lost in thought as he stared Beckett staring at a murder board – Miriam Borden had been found dead in an apartment that wasn't the one she shared with her husband – he plotted exposition in the back of his brain as other officers brought in next-of-kin, witness, even cuffed suspects who bellowed obscenities between the words 'innocent' 'wrong guy' and 'lawyer.'

Then again, Castle was fairly certain he could block out nuclear war when he watched his favourite brunette work her investigative magic. Her hair was slightly dishevelled from pulling her fingers through, as though follicle tension would help her concentrate, and her face was showing signs of strain and fatigue. He watched that full mouth set in a line; on any other woman it would be a sexy little pout. On Beckett it was determination, and it made Castle want to bite that full lower lip. The jolt of that realization some months before, especially after spending the summer apart from her, had left him always a little stirred up when he watched her work.

'What do you think?'

Castle blinked slowly as she turned those tired green eyes on him. 'I think it's time for a break, tear your eyes away from the world's easiest murder to solve. We're obviously looking for Shea Borden, his prints are all over that room and he's known for colouring outside the lines on his marriage certificate. Sit down and drink you latte.'

'You're right.' And Beckett rarely hated to admit that these days, but it made her feel a little uneasy that she had someone so interested in her personal well-being that wasn't Lanie or her father. Sighing, she turned away, sat at her desk and reached for the now-cold latte she hadn't even asked Castle to bring her. A little smile crept over her face as she sipped; though the coffee was glacial it was sweetened with the vanilla syrup Castle kept hidden in the break-room for her.

She looked up, saw a befuddled-looking Esposito staring at his phone. 'What's the deal?'

'That was Ryan. He's on his way in, he's got big news, apparently.'

Castle joined in Esposito's confusion. 'I thought he was taking some time off to spend with Honey-Milk, looking after her mother.'

'Well, whatever it is, he sounds like the little kid who found the secret decoder ring in the Cracker-Jack box.'

'Isn't that Ryan all the time?' Beckett asked blandly, skimming over the ME's reporter.

Castle saw what she was doing, and nipped the file from her fingers. 'No. Coffee time multitasking means letting your senses be aroused by the aromatic brew. Or because you let it go cold again, it would be closer to an assault.'

'Some people like their coffee cold.'

'You don't.'

'You know, Castle, you're not-'

'I never said a-'

'Guys!' Esposito cut the bickering off as a stupendously giddy Ryan practically floated into the room and over to the trio at Beckett's desk. He turned to face his partner, whose youthful Irish face was glowing with excitement. 'What's going on bro?'

Ryan's face split into a wide grin. 'Jenny and I got married last night!'