Set during 'Watersheds' chapter 4.

A domestic interlude, five days after Sherlock's return and John's rescue.

John should have known it was too good to be true. After all he knew his loves. He'd shared digs with Mary for several years whilst at Uni, and he'd lived with her for eighteen months. He knew the behaviours that made her incandescent, and he knew when to stay well clear of her for fear of inciting her temper. Similarly, he'd lived with Sherlock, experiencing his near pathological need to explore even the most personal of possessions, his inability to overlook things that were best not poked, his need to push boundaries until they snapped, and of course his complete disregard for basic safety protocols unless it suited him.

Mary was methodical with everything in its place, whilst Sherlock was methodical in a complete chaos 'but I know exactly where I put it' way.

John knew this, yet was still surprised when he came home the next day to find Mary red faced and threatening a tight lipped and indignant Sherlock, still in his pyjamas and dressing gown from the night before, with what appeared to be a half empty milk carton.

"Um, what's going on?"

Both parties started talking at once. Sherlock in his measured tone that usually indicated he didn't understand, and Mary in her deep and barely controlled 'I'm bloody angry and if this isn't sorted out I may do murder' voice.

"He's left it out all day. It's unusable. And it was our last one. I'll have to go out again …"

"I don't know. This woman you brought into my home has accused me of trying to poison her. And why should I buy more? I never buy milk. That's always your job …"

John held his hands up, closed his eyes and shouted "SILENCE!" As both voices stopped and two pairs of eyes looked at him in shock, he continued. "I am going to take my coat and shoes off, then I am going to the loo, and then we will sit around the table with a cup of tea and sort this out like the civilised adults we are."

"But, the milk …"

"Sherlock, could you please nip downstairs and ask Mrs Hudson if we can borrow a jug of milk."

Sherlock nodded and slunk past the still scowling Mary who was trying to rein in her temper.

"Mary, can you stick the kettle on. I'll just be a minute."

By the time he returned, Mary and Sherlock were sat at opposite ends of the kitchen table glowering at each other, a jug of milk placed in front of the empty chair on one side, presumably John's seat and deemed to be neutral territory by the warring parties.

Just as he returned, the kettle clicked off. He walked to the cupboard, withdrawing three mugs which he automatically checked were clean, a habit he'd never been able to shake even while Sherlock was away. As he allowed the tea bags to steep in their respective mugs, he placed the sugar with a clean tea spoon at Sherlock's end of the table. Like himself, Mary did not take sugar in tea.

Having removed the tea bags, he placed a mug in front of Mary and Sherlock, before seating himself at the table. He poured milk into his tea first before offering the jug to Mary. Sherlock glowered slightly, but pointedly added two teaspoons of sugar to his mug, stirring the tea slowly as he watched the progress of the milk jug. Mary returned the jug to John who now passed it to a simmering Sherlock.

"Put the lid on the sugar please Sherlock." John knew this was a power play. Sherlock had deliberately not put the lid back on the sugar bowl when he'd finished to goad Mary. It was part of the standard Sherlock playbook. Little digs to see how far he could push, how much someone could tolerate before they either exploded or walked away.

"Right. I would ask you what happened, but I can guess." He held up the offending carton, turning it slowly in his hand as he spoke. "Sherlock got out of bed, couldn't be arsed to shower, but did shave. Threw on his dressing gown, and spent the day doing whatever whilst making himself cups of tea. Being Sherlock, he left the milk carton out on the work-surface rather than returning it to the fridge, where Mary found it when she got home, in need of a cuppa, but well aware of the effects of storing milk at room temperature, especially if it is on a short date, as this carton is."

"John, you know there is absolutely no point in returning milk to the fridge every time I make a drink. It's a waste of energy."

"It's also a waste of milk." Mary chimed in. "You're a chemist Sherlock. You know the growth rate of bacteria significantly increases at room temperature."

John suddenly had an epiphany. "Sherlock, is this why we were always out of milk, or it was labelled as an experiment? Is it because you'd left it out all day?"

Sherlock looked directly at John, chin up in determination, like a little boy caught out in a misdeed. It was a look John adored, even if it meant Sherlock had done something wrong and knew it. "It was an experiment."

Mary threw her hands up in resignation. John tried not to let Sherlock see his smirk but failed miserably.

He took a sip of tea.

"Well, it's quite clear to me that this will not be the last argument we have as we learn to live together. So how about we clear the air now. Set some ground rules, before one of you kills the other. I love you both, so I'm not prepared to let this fester until you hate each other. We've all got too much to lose. Do you agree?"

"Yes, John" two voices answered almost simultaneously.

John stood, collecting a notepad and pen from the desk drawer, before returning to his seat. He knew both his loves were strong willed and set in their ways. The trick was going to be getting them to compromise to a workable solution without Sherlock becoming belligerent or Mary losing her temper again. And without John needing to go for a very long walk. He'd already ear-marked himself for the trip for more milk, if only to allow himself space to cool down, but that would have to wait for later. Now he needed to nip this potential cataclysm in the bud.

"OK. I'm going to make a list of things that annoy us. We will do this without shouting or argument. This is a logical exercise to identify as many problems as possible, not to argue about them. If it's on the list then it's upset someone and needs addressing, whether other parties agree on not. OK? Right, let's start with the milk."

It took over twenty minutes for John to list all the gripes. The usual suspects in multi gender habitation appeared, sanitary products in the bathroom, bristles from shaving in the basin, etc. John raised a few that he knew would come up in the future, but which neither Mary nor Sherlock had yet experienced in the short time they'd lived together. For example, John knew that, when sorting the laundry, Mary was a sock tucker, holding the tops of the pair together and tucking one over the other. Sherlock liked his socks rolled so that they fitted properly in his index. John had tried to persuade Mary to roll socks, but she argued it took too much time in comparison to her much quicker method. It was just one of many things that John knew would cause strife at some point, so best to get it aired now.

Next came the onerous task of agreeing a way of dealing with each item on the quite extensive list.

Every time they agreed to something John added it to the list of house rules. After over an hour of discussion and argument everyone was beginning to feel hungry. Tempers had calmed, and Sherlock was beginning to have some understanding of why some of his behaviours had previously made John so irate. Of course John used to walk away. It was apparent that Mary was not going to be so forgiving. Sherlock had to accept that some of his behaviours were no longer acceptable. Although, many of those were originally ways of testing the resilience of potential flat mates. Unfortunately too many of them had become ingrained as habits. When John had shown his durability, Sherlock had managed to shed some of his more contentious foibles, but too many had lingered.

Having spent over two years away, it was entirely possible that many of his old habits were broken. The milk had been something he had always done in his home. Having been back only five days, he was desperate to reclaim his old life. What he had to accept was that reclaiming his life did not necessarily mean reverting to his old ways, especially if it was going to cause strife with the person he most wanted to spend the rest of his life with.

Of course, it wasn't just Sherlock whose actions were causing upset. Mary had to accept that Sherlock had never lived with a female. Unlike John, there were some things that Mary did that would need some adjustment by Sherlock. The bathroom was a significant issue. When John and Mary had organised the refit of flat C they'd also had the kitchen and bathroom updated. A new bathroom suite, ample storage, and heated towel rails had been installed. John had also insisted that there were multiples of several fittings; three toothbrush holders, three shelves at different heights in the shower, three hooks on the door, etc. Sherlock had to accept that there were personal items that Mary needed to keep in the bathroom that Sherlock had to stay out of, and was strictly banned from using for experimentation. He also had to understand that, with only one basin shared between three adults, it was down to each of them to clean up after themselves. Of course, the age old argument of the loo seat up or down would not be an issue. All three were well aware of the horrors of flushing with the lid open, so at least they would always find the loo seat down, lid closed.

"OK, how do we solve the problem of the milk?" John knew there were simple answers to both the milk and sugar situations, but it was whether either party would accept the solution he proposed. "The simple answer is either for Sherlock to keep his milk in a separate jug that can stay out during the day, or we buy a small carton of milk for Sherlock and a large carton for general use." John looked between his two flatmates as they contemplated. Really, it was Sherlock who had to agree. It was his behaviour that had caused the problem, so it was down to him to accept any solution.

Sherlock hummed, his eyes focussed on his fingers that beat out a gentle rhythm on the table top. His mouth twitched to one side as he contemplated. Both John and Mary thought he looked adorable, although neither would voice their opinion, certainly not to the cantankerous git at the other end of the table who had them hanging on tenterhooks.

"A small carton for my use would be acceptable. I actually prefer whole milk in my tea and coffee, rather than the semi-skimmed you normally buy John. Perhaps several small cartons of whole milk and a large bottle of semi-skimmed would work well."

Both John and Mary sighed in relief. "Agreed. That will also make it easier when you're down in the lab. You'll be able to take your milk with you."

John clapped his hands together. "Well, now that's sorted, I'll type this up and stick it on the fridge. Anyone fancy dinner? I'll pick something up on my way back from Tesco."

Both Mary and John made to rise from the table, but Sherlock remained immobile. "No John. We're not finished. What is the penalty?"

Mary raised a questioning eyebrow. "Penalty?"

"Yes. The penalty for failing to comply. For breaking our rules. If we are to have laws to force us to conform to societal norms, we must, by definition, have punishments for contravening those restrictions. So I ask again, what will be the penalty?"

John felt a sense of creeping panic. Sherlock was always too clever. He should have known that simply agreeing to a set of rules was too simple. Of course Sherlock would agree, but he would still endeavour to manipulate the situation to his own advantage. Frozen half in and half out of his chair, he decided his best option was to sit back down. His eyes danced unfocussed across the kitchen table as his mind desperately sought a solution.

"Oh, that's simple. We each have our own. It's quite obvious the same thing won't work for all of us, so let the punishment fit the perpetrator and the crime." Mary stood at the end of the table, arms crossed, looking a little self-satisfied with her proposal.

John cast his gaze to her, not entirely sure where she was going with this, but feeling she was calculating enough to take on Sherlock, in this at least.

Sherlock looked at the woman at the opposite end of the table with a look of contemplation. Strangely, at this moment his deductive skills were failing him. He could see Mary had a plan, but for the life of him he was not entirely clear on what that was. He settled for simplicity, in the hope she would not realise his bemusement.

"Interesting. Continue."

"The penalty is to correct the infringement to the satisfaction of all, and to perform some task for the benefit of the injured parties. For example, Sherlock would have to do the shopping, following a list, for a week, and put the shopping away properly. I hate cleaning the bath, so I would do that for a week …"

"And roll my socks."

"Yes Sherlock, and roll your socks."

"Oh, I like this." Sherlock almost beamed at John, before turning his grin to Mary. "You're very good."

Mary smiled back. "I know, and I'm glad you've noticed. There are times when you're not too bad yourself." She tried to suppress the giggle that wanted to burst from her, and nearly succeeded, ineffectually hiding it behind a light cough.

Sherlock nodded his head in acknowledgement of the compliment, his obvious delight at the interplay of wits clearly visible in his sparkling eyes and gentle smile.

"Ahh," said Mary "but what about John?"

"Yes," agreed Sherlock "what punishment would be appropriate for John?"

"Hmmm, it would have to be something he dislikes."

"Yes, something he tries to avoid if at all possible."

John sat back with a feeling of smug superiority. "Good luck with that. I already do most things around here anyway. Admittedly not so much since you buggered off Sherlock, and Mary moved in, but I'm fairly sure that there is nothing you can find around the flat that I haven't done on a regular basis." John sat back and crossed his arms, secure in the knowledge that there was little they could find that could be referred to as punishment.

"Oh I don't know. I can think of a thing or two."

"Really Mary?"

Mary smirked. "Sherlock, have you ever seen John do the dusting?"

John glared at her "No Mary, please. You know it makes me sneeze."

Sherlock looked between his two flatmates. "No, I just assumed …"

Mary grinned. "I bet it was Mrs Hudson. John loathes dusting, and he's not exactly fond of vacuuming either."

Sherlock grinned. "Really? Well then, that seems an appropriate punishment. And I'm sure Mrs Hudson will appreciate the rest if, in fact, she has been doing the housework all along."

"Well, she was before I moved in. We tend to split it between us now. I think she likes to feel useful, so she dusts while I vacuum. We have a natter and finish up with tea and biscuits. It's our Friday morning ritual."

Sherlock brightened. "So this Friday, will you be at home?"

"Yes. I work from home on Friday mornings. It gives me a chance to finish the paperwork from the week and prepare for the following week. It only takes an hour with Mrs Hudson to get the flat spick and span."

"Then, if you have no objection, perhaps I could join you. I would like to catch up with everything I have missed and there is no better source of local gossip than Mrs Hudson."

Mary smiled and nodded her assent. "I don't see why not. Perhaps you could help Mrs Hudson dust the high shelves. She's not as limber as she was and is finding the stretching difficult."

"I suppose I could. I would not want Hudders to strain herself. She is far too valuable."

John watched in shock as his two loves bantered back and forth before reaching agreement. That Sherlock had agreed to help with the dusting was a minor miracle, but that the two were now smiling happily at each other was both heart-warming and alarming. He had expected to be the mediator in the relationship, and that they had come to an agreement themselves, without him, left him feeling a little adrift. Proud, but definitely adrift.

"Now that leaves us with John's punishment. I agree with you about the housework Mary, but one week seems insufficient, after all it is only one morning's work."

John took umbrage. "Oh, come on. I'll be sneezing all day if you make me dust. Isn't that punishment enough?"

Sherlock looked to Mary, who quirked her mouth to one side as she considered. She finally gave a little nod, and Sherlock gave a small smile in acknowledgment. "Then we agree. Dusting and vacuuming for one week, but no tea and biscuits with Mrs Hudson."

John dropped his head into his hands, before brushing his fingers through his hair. "Agreed. Now, can we please have dinner? I'm starving." And as if to underline the point, his stomach gave a loud growl.

Mary stepped round the table and threw her arms around her fiancé's shoulders. "Oh my poor baby. All this talk and no food makes John a grumpy boy. What do you fancy? I suppose it will have to be takeaway as his nibs hasn't washed today."

John turned in Mary's embrace to return the hug. "How about Chinese? If you order I can pick it up on the way back from buying milk."

"That sounds like an excellent plan. Chinese it is. Do you think you'll be able to survive the long hike to the supermarket?" Mary simpered playfully as she ruffled John's hair.

Sherlock stood from his end of the table and replied with absolute conviction. "Of course he can Mary. He invaded Afghanistan."

John turned to look at his love as his face broke into a grin. "That wasn't just me."

Sherlock smiled back for a brief second before both men collapsed into fits of giggles. Mary stood looking bewildered, not understanding the meaning of the conversation, but appreciating that it was important to the two of them. As John and Sherlock slowly pulled themselves together, it was as if a subtle shift had occurred between them. Some small barrier that had remained since Sherlock's return five days previously had somehow been broken by the ridiculous exchange. As she retrieved the phone from the coffee table and picked up the takeaway menu, she smiled to herself, comfortable in the knowledge that another hurdle had been cleared and a greater understanding had been reached in their on-going relationship.