A/N: I... couldn't help it. Dear readers, I confess, my love for Mycroft is unparalleled, therefore when my brain popped this idea for a Johncroft setup into the cloud of ideas...

Sorry. It's a weakness of mine.

To be fair to myself, though, it is my only weakness.

(I lie. Moriarty is my other.)

Yours,

The Plot Ninja

Rhythmic steps of a tall man echoed on wooden flooring. A light gait, someone thin and certain in their stride. Considering the imposing grandeur of the manor, there were very few people that could fit this category.

'Little brother,' Mycroft exclaimed without looking up from papers on his sturdy oak desk. 'How lovely that you would visit.'

'When one's own brother requests to see you, isn't it only polite to oblige?'

Mycroft rolled his eyes and pivoted in his chair, surveying Sherlock coolly. 'Polite, yes; however, with the pleasure of having you for a brother, whether or not you will turn up is a gamble at best.'

Sherlock shifted in the doorframe, already becoming bored. 'What do you want, Mycroft?' he drawled.

'I'm concerned for you, Sherlock. That is all.'

Sherlock scoffed. 'Your concern is truly touching, you can be sure. But you wouldn't call me in for just that. Something must have changed, or you wouldn't have bothered.' His silver-blue eyes searched Mycroft's passive face, hunting for clues; then suddenly he narrowed them, cat-like and suspicious. 'You reinstalled the cameras, didn't you?'

'They're for your own safety, Sherlo-'

'No, Mycroft,' Sherlock interrupted. 'They're to satisfy your own need for complete control.'

Seeing no headway being made in the argument, Mycroft cut to the point. 'I'm worried about the change in the relationship between you and your flatmate.'

'You mean you're jealous.'

'No, I...' How did Sherlock make such distant jumps to conclusions. 'Why would I be jealous, pray tell?'

A smirk from the sleuth. He wandered over to the chair opposite Mycroft's desk, planting his hands firmly on the back of it and leaning over. 'He's just your type.'

Mycroft didn't seem to want to dignify this with a response.

'Come now, Brother-dear,' Sherlock chided mockingly. 'You've always liked the strong-willed ones. Ones that you have to work to intimidate.'

The older man pulled the papers in front of him into a tidy pile, setting them to the side, before looking up at his sibling; Sherlock was grinning smugly like a Cheshire cat. 'It's irrelevant, anyway,' he said hastily. 'I wanted only to remind you: Caring is not an advantage. Don't go developing feelings for this man, just because he's the first person able to tolerate you.' Aside from myself, he didn't add.

Now it was Sherlock's turn to roll his eyes. 'You're a fine one to speak. Don't bother yourself, Mycroft – my little experiment yesterday was purely physical, as you would know if your delicate sensibilities didn't restrict you from monitoring John's bedroom. And now, I must get home; there are fifteen... no...' He scrutinised Mycroft's face again. 'Seventeen cameras that require disassembly.'

'Hold on,' Mycroft called to Sherlock's retreating back. 'You're giving me the green light?'

Sherlock shrugged. 'You might be the one able to bring my flatmate out of the wardrobe.'

'Closet.'

'Indeed. I require him left in a state fit enough to chase criminals; aside from that, he's yours.'

And with that, the lanky man strode from the room.

Not ten seconds later, his head reappeared around the doorframe. 'And Mycroft? Don't scare this one off. You have no idea the difficulty of finding tolerable flatmates these days.'