The rain outside 221B Baker Street is relentless, drumming a steady, monotonous beat against the windowpanes. Inside, the sitting room is a chaotic landscape of stacked books, chemical equipment, and the faint, lingering scent of tea and tobacco.

Sherlock Holmes stands in the center of the room, looking down at you with an expression usually reserved for an unexpected and highly inconvenient biochemical anomaly. He wears his dark dressing gown, hands buried deep in his pockets, his pale eyes narrowing as he processes the situation.

John Watson stands by the door, having just waved goodbye to an incredibly stressed, rain-drenched Inspector Lestrade, who had to rush off to a sudden breakthrough in a case. "John," Sherlock says, his voice a low, analytical drawl. "It is five years old. Or possibly six. Its motor skills are still developing, its cognitive reasoning is elementary, and it has been staring at that skull on the mantelpiece for exactly three minutes without blinking."

"She, Sherlock. She is Greg's daughter," John corrects patiently, taking off his jacket and sighing. "And you promised him you’d help out for a few hours. It’s just babysitting. It doesn't require a master plan."

"Babysitting is an inefficient use of my time," Sherlock mutters, though he takes a step closer to you, his coat swirling slightly. He crouches down, bringing himself to your eye level. His sharp, piercing gaze sweeps over you—noting the small smudge of mud on your left shoe, the slightly crooked button on your coat, and the bright, curious way you look back at him.

The frown on his face softens just a fraction, replaced by a glint of intellectual curiosity. "Well," Sherlock murmurs, tilting his head like a raven. "Since you are here, and since your father lacks the basic foresight to provide you with adequate entertainment, we shall have to find something to occupy that primitive brain of yours."

He reaches into his pocket, pulls out a small, shiny magnifying glass, and offers it to you by the handle.

"Here. Take this. There is a trace of unknown atmospheric residue on the leg of the coffee table. Go examine it and report back your findings. And do try not to touch the test tubes in the kitchen—they contain things that would make your uncle Greg very cross."