"Oh, Sherlock, Sherlock," Mrs Hudson threw up her hands. "When will you grow up? Men are just like children. My husband was just like that, too!"
John has already stopped being surprised by the comparison of his eccentric flatmate with the executed by the electric chair for unknown to Watson crimes Mrs Hudson's late husband and slowly moved his gaze onto the excitedly crawling on the floor Sherlock, who was, for some reason, assembling a toy railroad.
Mrs Hudson gazed at the detective, who was puffing hard in concentration, and left to attend to her other landlady duties.
"Oh, Sherlock, Sherlock," John repeated with a crooked grin, "why did you enter a second childhood all of a sudden? Did you run out of bullets or simply decided to have mercy upon our unfortunate wall?"
"Don't interfere, John," attaching another piece, Sherlock said dismissively. "On this assembly, depends..."
"Someone's alibi," John resignedly finished the sentence, imagining how on this quiet Saturday night he'll have to run somewhere and chase someone down, as soon as Sherlock proves whatever it is he intends to prove. "Maybe it's simply because you had wanted to be a train driver when you were little?" snorted John.
"John," Sherlock immediately glared daggers at his flatmate. "Mycroft has, most likely, enlightened you as to what my childhood fantasies had been."
"Oh yes, a pirate. Of course, it would have been a pirate," suppressing a smile with an effort, muttered John. "I do wonder who Mycroft wanted to become?" John thought all of a sudden, imagining Holmes the senior in his childhood years: somehow, in his imagination, even mini-Mycroft never let go of his favourite umbrella.
"Oh, Mycroft..." Sherlock snorted, "Mycroft, as I recall, had always wanted to become some kind of...nanny."
"Nanny?" John goggled at the detective, thinking if he hadn't misheard.
"Yes, he kept running about the house with his umbrella open, yelling, 'Winds of change, winds of change!'"
"Well, his dream did come true, in part," John muttered aside, imagining Sherlock's brother in the role of the character from the well-known children's fairy tale. "Be careful what you wish for, the wishes tend to come true in the most unpredictable ways."