Being his brother's keeper had never been a hardship for Mycroft, and yet as Sherlock's thirty-first birthday approached he found himself wondering whether the time had come to choose a proper handler for his wayward little brother. Greg Lestrade was doing as fine a job as could be expected from a man in his position, but even he couldn't be around Sherlock all the time.

Perhaps he'd better consider the idea of marrying off his recalcitrant sibling to a suitable candidate; someone who would endeavour to keep Sherlock out of trouble as much as feasibly possible, without succumbing to the urge to throttle the insufferable brat. His brother might be asexual and ostensibly married to his work, but even he wasn't completely immune to intellectual attraction and the benefits of companionship.

When he was informed about Sherlock's new flatmate he didn't think for a second it could be a mere coincidence; the universe was rarely so lazy, as Mycroft knew only too well. The vast majority of people immediately assumed that the consulting detective and his blogger were a couple, much to Dr Watson's dismay and Mycroft's secret amusement.

Mrs Hudson, the landlady, wrinkled her nose in disapproval every time John brought a girlfriend to the flat, no matter that he always claimed he wasn't actually gay. The former army doctor eventually stopped trying to correct other people's assumptions, contenting himself with basking in Sherlock's friendship and the thrill of the danger he still missed from his days in Afghanistan.

Then came the day when a criminal they were chasing shot John Watson in the leg, and for the first time in his life Sherlock was thrown into a state of panic. Courtesy of a conveniently placed CCTV camera Mycroft watched as his little brother tried – and failed – to talk his way into Intensive Care, pretending to be John's adoptive brother. The incident was the proverbial straw that broke the camel's back, planting the idea of marriage in Sherlock's reluctant mind.

The day after Dr Watson was released from hospital Sherlock dragged him to the register office to give notice of their intention to get a civil partnership. Mycroft couldn't help looking as pleased as the cat that got the cream, as his PA pointed out wryly. He was in such a good mood that he didn't bother to lecture not-Anthea on the inappropriateness of such a remark; he phoned Lestrade then, informed him about Sherlock's intentions and strongly advised the DI to accept his role as a witness.

Lestrade huffed in disbelief, but in the end the Scotland Yard man simply yielded and attended the ceremony along with Mrs Hudson. Mycroft made sure that a congratulations card was delivered to 221B Baker Street, along with a cheque by way of a wedding present. He could easily picture John's flustered face as he read it, and that was an added bonus to the knowledge of having just outwitted his irritating little brother.

John Watson would keep Sherlock in trouble but not exceedingly so, saving the younger Holmes brother from boredom and sparing the elder from constantly worrying about his sibling. As for the nature of their marriage, Mycroft was wise enough not to push his luck by broaching the subject with his newly acquired brother-in-law. He figured that John himself couldn't quite understand why he'd unexpectedly given in to Sherlock's seemingly absurd request, and he wouldn't be the one to foster the seeds of doubt that already troubled the doctor's mind.

xxx

If there was something Mycroft Holmes loathed, it was being wrong, and yet he couldn't deny how badly he'd misjudged the situation when he'd driven his baby brother into Irene Adler's path. That woman was everything Sherlock felt drawn to – clever, manipulative, beautiful and dangerous in equal parts. Mycroft only allowed himself to heave a sigh of relief when he was reliably informed that The Woman wouldn't be an issue anymore.

Obviously he was well aware that Ms Adler was no more dead than she'd been the last time around, and that Sherlock knew he knew. Still he carried on with the farce, mostly for the benefit of a certain John Watson who seemed to take the whole debacle too much to heart for Mycroft's liking.

It wasn't that John hadn't tried to pull women after entering the civil partnership with his best friend; Sherlock had even encouraged those half-hearted attempts, though the repeated failures were proof enough that the doctor didn't really care the way he used to. That being said, even a blind man could tell that the Irene Adler business had upset John far deeper than he was willing to admit.

Because John Watson might still be adamant about the fact that he wasn't gay, and claim that he and Sherlock weren't a couple in spite of their unconventional marriage; and yet their platonic relationship mattered to him in ways the good doctor couldn't quite understand, never mind Sherlock 'I'm-married-to-my-work' Holmes.

That was why Mycroft stood in the rain waiting for John to show up, fed him the lie about The Woman's untimely demise and waited for him to pass it on to his husband. Sherlock texted later that day, asking his big brother whether he was growing sentimental with middle age; that was code for 'thank you', and Mycroft simply took it at face value.

xxx

The unlikely marriage of convenience carried on successfully until Moriarty grew tired of waiting and set his elaborate game into motion. Then Sherlock took a swallow dive off the rooftop of St Bart's Hospital, and Mycroft was left to pick up the pieces of the grieving widower.

John moved out of 221B, hoping against hope that this would help him move on with his life as well. To his credit, Mycroft had to admit that the good doctor didn't look nearly as surprised as he thought he would when Sherlock resurfaced two years later. He still refused to speak to his husband who'd just come back from the dead for a good three weeks, during which Sherlock seriously considered swallowing his pride and apologising – though he couldn't quite figure out whether he should apologise for pretending to be dead, or for coming back.

However, Mycroft knew that John would come around eventually. He'd already instructed his PA to purchase a small cactus in a pot, which he was going to send as a housewarming present once Dr Watson moved back to Baker Street.

Cactuses stood for endurance, after all.