"You look nothing like my Dad," the child murmured pensively, hugging her knees to her chest.
He shrugged noncommittally. "That's what I told our parents on more than one occasion. They assured me we're brothers though."
"Should I call you uncle?"
"I'd rather you didn't, if you don't mind. You can call me Sherlock."
Her gaze was fixed on his hands as he rubbed rosin on the bow hair, then lovingly picked up his violin. "Stradivarius?"
"Yep," he confirmed, popping on the final 'p'. She held her breath as he coaxed the first note out of the instrument, her fingers beating out the rhythm on the armrest.
"May I?" she ventured to ask as the last notes of Bach's partita number one still hung in the air.
Sherlock wordlessly handed over the violin, studying the little girl as she assumed the right posture and played the same composition without a single hesitation.
"You're a natural. Mycroft is right, you'll grow into a fine violinist in no time."
"Savant child, remember?"
"I expect that's half the reason why Andrea chose you over the other candidates for adoption."
Rosemary furrowed her brow, as if weighing the possibility. "Could be. Dad's weird like that. Papa is the sensible one."
"That's fine. Greg is the conscience to Mycroft's reasoning. Pretty much like between me and Molly."
"What does that make me then?"
He paused, considering. "You're the heart, I guess."
"Melissa is lucky to have you," the girl declared, crouching beside the armchair to stroke Copper's ginger fur; the cat purred contentedly and arched into her touch.
Sherlock raised an eyebrow in amusement; he suspected he was the lucky one, as was Mycroft for that matter.
Not that he was going to spell it out loud for his pompous, overbearing big brother anytime soon.