Don't Blink, Mr Holmes. I've got the Winchesters to Help.

Thumb in the Petri Dish

"Good morning, Mrs Hudson." Mycroft's words were precise and direct; they almost had a plummy feel to them. 

"Good morning, Mycroft," Mrs Hudson stepped aside to allow space for the older Holmes to enter the flat on Baker Street, "The boys are upstairs having breakfast." This last part was unnecessary, but Mrs Hudson often liked to do this: add a little extra information, just to make sure it was clear. There was nothing wrong with this, John actually thought it was quite nice where every situation Mrs Hudson directed him to, it wouldn't be completely blind. 

"Thank you, Mrs Hudson." And Holmes swept up the stairs to his brother and flat-mate's apartment. 

"What do you want, Mycroft." This wasn't a question, but a statement Sherlock Holmes said as the distinguishable noise of sharp footsteps came to a halt at the top of the stairs. 

Mycroft entered the room to a scene, one almost domestic. The table carried a tray with a pot of tea, a sugar bowl and a milk jug, two mugs, a toast rack (one piece remained), a jam jar (half done), a butter dish with a slab of rich yellow fat on it, two plates covered in crumbs and a couple of jam smears, two knifes and two teaspoons. The room was almost completely tidy, yet if it had been cleaner, the scene would have looked false, not homely. There was nothing in the room to say that a sociopathic man and a ex-army doctor that solved mysteries and murders lived there. 

Well, the thumb in a petri dish on the kitchen table was the only thing wrong in the layout before Mycroft. 

"I need your help." 

Sherlock was reading the daily paper in his blue dressing gown, "My help?" He glanced up once then back down at the paper. It was an article about he and John's most recent solved case. "Something's happened and you need me to figure out what. It will more than likely mean me leaving London on a trip somewhere in America. Your morning tea was a bad one, you became agitated and were unable to finish it." It had been two days since their last case, and Sherlock had deduced John so many times he knew down to the exact second how long John took in the shower each time (it varied, for some mornings John would be a little more tired and he'd spend longer washing his hair, whereas other mornings he'd be up bright and early and have a quick whack in the shower. Sherlock had seen a remnant of some spilled semen left on the very edge of the door.) 

Mycroft merely sighed and took a seat in the armchair that faced the breakfast table. 

Up until this point, John had been finishing his last piece of toast and just glancing between the two brothers. It was when he swallowed the last bite and wiped his mouth on a napkin, he raised his eyebrow questionly. He knew that Sherlock did this, but still, every single time he was struck at the brilliant skills Sherlock possessed. So he never asked now, just expected the explanation. Sherlock had always been happy to oblige.

"You're carrying a briefcase, but it's a different one from your usual one. This one has a different lock on it, and a small logo on the side. It's the symbol of the American UNIT. Something has happened in America and you want me to go over there and find out and see if I can solve it. You received the news of something bad happening in America this morning, halfway through you taking a sip, causing it to spill on your cuff - there is a small stain on your left - this made you mad and you didn't want to finish it, considering half of it was on the floor. Am I wrong?" Sherlock folded the paper closed and chucked it to the sofa.

"No, brother, you're not wrong." Setting the briefcase across his perfectly angled knees, Mycroft turned the dials and clicked it open, revealing a neatly stacked pile of papers and photographs. "Two days ago a real estate agent that worked undercover for UNIT went missing from a house in Colorado." A photo of said estate agent was produced from the pile. "She'd been sent there on a mission to discover more about Bathory House. Yet she never returned. Her car was still outside with her personal belongings in it." Mycroft paused and handed over another photograph. "Even the keys." 

John tilted his head and raised it to look at Mycroft. "That's that house where all the teenagers have disappeared from, right?"

"Right." Mycroft pulled out some sheets of paper. "These are reports of all those that have went missing." Another couple of sheets, "Details of the house," sheets, "And some documents you'll need to sign to leave the country under my control."

"We never said if we'd do it.." John countered, a small smile on his lips. Of course they'd agreed. Sherlock was craving something new. 

Before Mycroft could close his briefcase, a pen was already signing the name of Sherlock Holmes on the required dotted lines.