Two
The meal at the restaurant went on for longer than Watson thought it would have done, with Sherlock being as veiled about his life as usual and guessing everything about Watson's life right down to his favourite colour. The pair took their time sauntering home as, despite the chilly weather, it was quite a nice night - crisp and refreshing, the moon shining brightly, accompanied by the few bright stars that weren't drowned by light pollution in the busy centre of London.
Eventually, they made it back to Baker Street, Watson's limp worsening in the cold. Sherlock leaned on the door frame and looked at Watson expectantly.
"What?" The doctor quizzed the detective, who smiled and chuckled to himself. "No really, what joke am I missing, or is it something that only sociopaths get?"
"Well, aren't you going to open the door?" The detective grinned his smug little grin at Watson, whose face fell. "What's wrong? Don't tell me you've forgotten the key..." Both men moaned, looked at each other and laughed.
"You're supposed to be the genius here, what kind of genius forgets house keys?" Watson chided Sherlock with a grin on his face, only being half serious.
"And you, my fine man, were in the military. What kind of military man forgets his keys?" Sherlock retorted, grabbing the drain pipe next to the door and looking up to see if there were any open windows further up the house. Alas, the cold night had obviously got to Mrs Hudson as she had shut all the windows.
"Oh shut up, I'm going to call Mrs Hudson." John said as he pulled his phone from his pocket. Within a few minutes, Mrs Hudson had shuffled down the stairs to let them in.
"Oh you boys, always galavanting off places together..." Before she could finish, John silenced her with an I'm-not-his-date look, Sherlock asked for her to put the kettle on, which she replied to with a call of 'I'm not your housekeeper' before going back into her ground floor flat and closing the door firmly.
"Looks like it's up to you then." Sherlock called as he almost flew up the stairs, removing his coat and scarf as he went and hanging them on the new coat rack John had insisted on buying, as he was sick of tripping over Sherlock's scarf all the time. At least if they bought things like coat racks and desk tidies it gave the illusion of it being a tidy flat, when underneath it was a crazy mess, which fit the owner of the flat quite well...
When John finally got up the stairs, clutching his leg, he went into the kitchen to put the kettle on and make them both a mug of tea. Watson stretched and turned to see Sherlock sitting by the window with his back to the room on the arm of his lounger, staring out and fingering the strings on his violin. He started to play a soft melody that was haunting and melancholic. Watson felt a pang of something in his gut as he realised that he was probably the first real friend Sherlock had ever had. It hurt him to think that the genius was being cast out as a monster just for being cleverer than most people and scarily accurate with his findings. The 'ding' of the kettle as it boiled snapped Watson out of his daydream and he shuffled back into the kitchen to go and make the tea.
"Thank you..." so faintly uttered from the lips of the detective that, had he not stopped playing the violin, John would have missed it altogether. Before he could answer, Sherlock had swept out of the room and shut the door to his bedroom.