Newton's Second Law: the net force on an object is equal to the rate of change of momentum

It had been well after 1 a.m. by the time Sherlock's theories had subsided to trailing sentences and bleary eyes, and Mycroft was certain he'd heard the clock strike an unseemly number of chimes when he managed to convince his brother to return to his room. Still, as a sullen dawn insinuated itself through the clouds, he dragged himself out of bed. Another weekend tradition had yet to be fulfilled.

His father was sitting at the kitchen table, nursing what appeared to be a second cup of coffee. Mycroft poured himself a cup and settled into the chair opposite, reaching for the first section of the paper that now lay discarded on the table. Siger was about halfway through the financial pages.

"Mycroft."

"Sir."

They made brief eye contact, before raising their respective papers. It always set Siger at his ease, seeing how much his oldest son emulated him. Mycroft had not been aware of the point at which the mirroring became instinctive rather than intentional, but the fact of it was undeniable. They held their papers at the same angle, raised their coffee cups at the same intervals, skimmed the pages with the same nearly-bored expressions. Add to that the fact that Mycroft had, without a doubt, inherited the Holmes nose, and the resemblance was positively uncanny. He tried not to let that thought stay too long in his mind.

The break-in at Delaney's nursery was still top news in the local paper. Mycroft glanced down the column of text, eyes attracted to the pertinent bits of information. Sherlock was right, Delaney's son was the only logical suspect. The intruder had clearly gotten in without violence and gone too far to make it look like a break-in. The damage to the store was overkill, betraying a personal vendetta aided by great familiarity with the property. Why else would the spigot for the irrigation system have been smashed? It was reasonably close to the door, but hardly a target when one was attempting to enter the building. Mycroft toyed with the idea of bringing it up to Father. Oh, and by the way, I agree with Sherlock. It was Delaney's son. The image almost made him laugh.

"Something funny?"

"Hm? Oh, just a typographical error." He'd actually spotted two thus far, so he'd have cover if Father pressed the point.

"Bloody incompetent editors."

Mycroft made a small noise of agreement and turned the page. The local news gave way to briefs of international news, which he skimmed. Nothing of importance.

His father twitched the paper to straighten it, then folded it beside his coffee cup and made a harrumphing sound. "Term going well?"

"Yes, sir." Mycroft did not lower his paper just yet.

"I don't suppose you've got much time for a bit of a side project."

He stifled a sigh. He had presumed as much. "It is possible I could find the time," he said, letting the paper tip forward to see his father's face.

The man had the grace to look slightly sheepish, as much as it was possible for Siger Holmes to look, but it quickly vanished.

"I've made a new acquaintance, you see, and I'm in need of some new –"

Mycroft found he did not have the patience for the usual dance. "I'll contact Fleming about getting a new credit account for you on Monday. When I have it, I'll send the information to your office. The usual code. Have you given her a name?"

"Davies."

"First name?"

"Siger."

"Unfortunate. It's not a common name. If she does much digging –"

"She won't," Siger said, raising his coffee cup to his lips. A slight smile stretched them to match the curve of the rim. "Not this one."

The rebellious part of his mind that still recognized things like morals and vows wanted to ask his father if it wasn't just a bit selfish to chase so many women of varying degrees of beauty and intelligence when he had a wife with an abundance of both. But Mycroft had learnt when he was only 6 that Father was happier when he had an intrigue or two to balance. And if Siger was happy, then life at home moved at an even keel, which was simply best for all involved. Sherlock had been a toddler the first time Mycroft helped his father cover his tracks. By now it was as much a tradition as Christmas eve pudding.

"Also, I need you to find a new hotel. Your brother ruined any chance of me going back to the last one."

Ah yes, the debacle last year that drove the most decisive wedge between the brothers. The first time Sherlock found conclusive proof of his father's infidelity and decided to tell Mummy. When he discovered Mycroft had been helping carry out the deception… well, Sherlock had never been one to tolerate illusions, no matter how well intentioned.

"What part of the city?" he asked, fingering the handle of his cup.

"Give me options. I'm not sure yet where she'll be coming from most of the time."

"Wouldn't it be more efficient to-"

Mycroft broke off as he felt the shift in his father's mood. He looked up to see Siger's lips tighten into a dangerous line. His eyes were hardening. The trigger point was easier to reach these days, apparently. Sherlock's homebound status, no doubt. He inclined his head slightly in acquiescence.

"I'll check into it and let you know."

Siger leaned back and took another sip of coffee. "Good."

Mycroft mirrored him. Habit, but one that held him in good stead. The sharp line of his father's shoulders loosened almost imperceptibly. He wondered, idly, if his father was aware of how easily he was manipulated, and how he would react if he ever found out.

"I know your mother invited you so you could try and work on your brother. Any success?"

There was camaraderie in his voice. Mycroft forced the recoil to remain internal and pushed down several of the more candid commentaries on his role as a parent in the situation.

"Oh, Sherlock doesn't take well to being 'worked on.' It's more a matter of letting him be heard that sets him straight, I think."

It was as blunt as he'd ever been with Siger, a fact that made him momentarily regretful. But a glance across the table made him realize it was not blunt enough. Siger was scoffing as if Mycroft had just suggested buying Sherlock a pony. And Mycroft hardly took his own advice when it came to his brother, so he couldn't expect his father to suddenly reform.

"I wonder sometimes," Siger said into his cup.

"Oh?"

"About his mind."

Mycroft's shoulders pulled back into a battle stance. "Oh?"

"There's something not quite right about him. You see it, too. You have to. He's all mind, that one. No emotion. No need for any sort of human relationship. I think I could shut him in his room with a chemistry set and he'd be content for a year."

"He's intelligent. I was, too, if you recall."

"Yes, but you were normal."

You were like me. The words hung unsaid between them. Mycroft ordered his lips into a smile of acknowledgement.

Siger drained his cup and shook his head. "Some days I think I ought to have him tested again. He's practically a danger to society, and only just hitting his teen years."

"He's never in trouble when his brain is occupied. Perhaps a more challenging school?"

"He's not coddled where he is. He stays. Unless they expel him after this last incident, that is. But they make him toe the line. It's good for him. Discipline. He stays there or he comes home and can make do at the local school."

Mycroft considered the ramifications of putting Sherlock back in the house with his father full-time, adding in the element of Sherlock being forced back into state school. This round went to Siger, no question. Even if Mycroft had to bribe Sherlock into behaving.

He realized a beat too late that his father expected a response. He raised his coffee cup in an attempt to cover for it.

"Well, I'm sure he'll rise to the challenge."

The incident regarding Sherlock's interference is explored in chapter 4 of my story "As We Are, As We Were."