Molly was so engrossed in the delicious tale in front of her that the sudden knocking at her door caused her to jump.
Her disgruntled feline fell off his comfortable perch on her knee and gave her a mutinous look.
She stared down at him and shrugged her shoulders, feeling only marginally ridiculous that she was justifying herself to her cat. Besides it wasn't like it was her fault. It was very rare for her to have visitors at all, let alone ones at this hour.
She got up off her sofa, sliding a bookmark to keep her place and ventured towards the front door.
The knocking came again, only this time more insistent.
She hesitated at her front door and leaned up to stare through the peephole.
Her eyes widened and she yanked the bolt back, unchained and unlocked her door, and gaped as Sherlock Holmes pushed past her and stormed into her apartment.
"Hi," she said as he threw himself on her recently vacated sofa.
"Yes, yes." He waved the social niceties away and slouched further down, looking every inch the petulant schoolboy.
Since she had helped him fake his death and had housed him for several months she had lost her hero-worship of the man. She could now hold tolerably intelligent conversations with him without regressing to a blushing schoolgirl. If she did have the odd fantasy where he came here to rip her clothes off... well, she was able to hide it a lot better now that she knew he liked to wear ratty dressing gowns and bit his nails when he yelled at Jeremy Kyle.
Still he said nothing and she closed the door and headed to the kitchen. She filled the kettle up and put it on, knowing that he would appreciate a hot coffee even if he was sulking.
She heard him huff a few times and went back to her living room.
He had his eyes closed and palms pressed together which meant that he was deep in thought.
"Difficult case?" she asked quietly, not entirely sure why he was there.
"Obviously," he intoned.
They were silent for a long minute during which Molly decided that it was time to get that coffee. As she stood up, Sherlock exploded.
"It doesn't make sense!"
She sat back down. "No?"
Sherlock surged to his feet and began pacing. "The legacy was handed down from father to oldest son throughout twelve generations, each one getting progressively smaller. But now a daughter has stepped out of the woodwork claiming the rights as the eldest. No son so the money would go to her. Problem? No one knew of the daughter but her DNA matches that of the father. Definitely his child but the father is sterile. It is impossible for the girl to be his daughter yet all the genetic markers are there. How is this possible?"
Molly waited until he gave her a glare. She jumped. "Oh, you're asking me?"
"Mrs Hudson took my skull," he bit out, "and John is… busy."
Molly bit her lip. "With Mary?"
It seemed that the relationship between the good doctor and the sweet paediatrician was getting serious. That would be enough to annoy Sherlock at the best of times but if he was having a particularly perplexing case then it would be even worse.
Molly sighed and walked into the kitchen.
Molly stirred his coffee, deep in thought. "Did he donate sperm at any point?"
"Is there a brother or sister, could she be his niece?"
"No." Sherlock paced. "Already checked. Not his niece or cousin or sister, the genetic markers are too close."
Molly paused. "How close?"
She heard him stop in his tracks.
"No, no, no. Yes. No. But what if- yes, of course! The mother!"
"Hmm?" She reached up for a flask she kept for work and poured his coffee into it.
He was waving his arms madly. "Don't you see? So simple. The mother always wanted a daughter but knew that any inheritance would go to her sons. So when the boy is born she ensures that he is sterile and uses her degree in genetics to manipulate further samples to procure a daughter. It takes some time so she can't pass her off as a daughter and has to make do with being a grandmother. It explains the two year sojourn to Italy and the dwindling of the inheritance. Wonderful!"
Molly frowned. "Genetically engineered children? It's a bit farfetched, isn't it Sherlock?"
"Not engineered, manipulated. The genes were already there she just had to tweak them. We've all heard of designer children. It is the only explanation that fits all of the evidence, Molly. As I have often said once you have eliminated the impossible, whatever remains-"
"However improbable, must be the truth," Molly finished with a smile. She offered him the flask. "Hot coffee, go be brilliant."
"I shall." He swept his scarf over his neck, gave her a devastating grin and raced out, shutting the door behind him.
Molly shook her head once, crawled back on her sofa and picked up her book.
"Now, Mr Darcy where were we?"