Sherlock Holmes was missing.
It took two nights for Mrs Hudson to contact John. Sherlock was known for just taking off, and John knew that, but something felt off. John in turn called Lestrade, and Mycroft a bit later. The latter attempted to track Sherlock's phone, but was left with nothing. Likely due to the phone itself being destroyed, he'd said.
Everyone was on edge. And everyone did their best to figure out how to find him. Lestrade organized search parties, contacting the Homeless Network as well. John and Mary went over everything in Sherlock's flat. Mycroft using all his resources to try to find his little brother.
Their options were limited, because Sherlock's trail essentially went cold, aside from just a few clues from the last case he'd worked. He had been missing for three days when John, sitting in Mycroft's office with nothing more than a vague notion, called the 'only in case of emergency' number they had for one Natasha Romanoff.
Natasha had been in the middle of a meeting with the rest of the Avengers when the call came through. John's name on the screen of her personal phone sent up an immediate red flag. Her number was private, and she'd given it to both John and Mary to use in case of emergencies only. Evidently something deserving of the name had occurred.
Excusing herself from her teammates, Natasha slipped out of the room to take the call. "John," she greeted quietly once she was alone out in the hallway. "What's wrong? What's happened? Where's Sherlock?" She glanced at her watch for the time. "Do you need me to come over?"
"Sherlock's missing." John said, far more calmly than one might expect. A waiting storm of a worried friend. "He disappeared three days ago, we've exhausted the other options. Mycroft thinks he's out of the country, but we don't know for sure." He took a deep breath. "If you can spare the time…we could use you."
Natasha gripped the phone just a little tighter and closed her eyes. "I'll be there," she said evenly. "I'll text you as soon as I get in and we can meet at his place. Shouldn't be more than three or four hours, I'm in Nice. France. Stark can fly me out." She paused. "I'll see you soon."
Once the call cut off, she opened her eyes and pocketed her phone. Bruce Banner's disappearance abroad had at least one miraculous silver lining. Time was usually of the essence in disappearance cases. Considering what Sherlock did for a living, that was truer in his case. Natasha slipped back inside the room and sidled up to Steve, pulling him aside to rattle off what few details she knew and excuse herself. Staging an intervention with Bruce Banner and asking him to come home was meant to be a group effort, but she could be spared.
Steve put himself at her disposal should she need his assistance and she promised to pull him into the fray if that proved to be the case. Bags packed, she waited for Tony to exit the meeting to approach him, and he readily made arrangements for her to fly out in his private jet. Within an hour and a half, she was up in the air and on her way.
Natasha was good in a crisis. She was calm and even tempered, capable of detached analysis. She'd trained a lifetime under the most extreme circumstances and these skills that were as much as part of her personality, as a product of careful cultivation. But the reality of the situation was that she'd never dealt with a crisis where someone she loved, the way she loved Sherlock Holmes, was in such immediate and unknown danger.
Regardless of the words they used to tell other people what they were to each other, to Natasha Sherlock was always home. She was in no way equipped to deal with even the hint of the possibility that her home might be taken from her. All the more reason to stay on point and focus. Cutting off those thoughts before they had a chance to get the better of her, she focused on coming up with a game plan. She was good at finding people and she'd apply the same methods to the task at hand. She'd find Sherlock, wherever he was, and bring him home.
Tony's jet landed in London after approximately two hours of flight time, and she climbed out to board one of Mycroft's private cars. The car ride was spent in silence once she'd informed the driver of her destination, and soon she was stepping out in front of 221B.
John was already inside. The good doctor was seated in his chair, hands fisted on the arm rests. He glanced up at her and got right into it without a greeting. "Mycroft has everything we know in a file. It's on the table."
"Including cases he last worked on?" Natasha asked, but her question was answered moments later when she opened her file and had a look inside herself. "I'm going to need Mycroft to have transport ready so we can leave as soon as we know where Sherlock is."
"I have no doubt he's got everything you need ready and at your disposal." John said, relaxing back into the seat. Not a calm relaxed, but an exhausted one. He hadn't slept much in the last day and it showed. "He's more than worried and working everything he can from his end."
Natasha didn't reply. Instead she picked up the file and carried it over to Sherlock's chair, never once ungluing her eyes from its contents. Receipts, printouts, pictures, call logs, and a number of other papers were flipped through in quick succession. She could follow Sherlock's steps through his last couple of cases to a point, but then hit a dead end. Every possible trail fading to nothing when followed to its conclusion. She reviewed the information again with the same result, and finally snapped the file closed. "There has to be something else." Rising out of Sherlock's chair, she moved over to his desk to retrieve his laptop.
"Mycroft went through his computer and emails, he couldn't find anything else." John said, his hands ideally playing with his phone in his lap. "Everything suggests Sherlock left of his own free will-" He was interrupted as the phone in his hands rang. John blinked at the blocked number that flashed on his screen and glanced once at Natasha, turning it to speaker phone as he answered it. "Hello?"
The voice at the other end was instantly recognizable, and Sherlock spoke quickly and quietly as he rattled off a series of numbers. "Lat 47. 3. 20. Long 7. 58. 56. I don't have much time-"
Natasha's head whipped around at the sound of Sherlock's voice coming from John's phone and in two strides was beside him with her own phone in her hands. "That's Switzerland," she spoke once she'd brought up the coordinates on her screen. "Near the Alps. Sherlock," she spoke to him next, apprehension evident in her voice. "Injuries?"
"Yes." Sherlock said, his tone further hushed than it was before. "Private militant group…he wanted revenge…no time left-" he stopped off as another voice came over the phone, shouting in German. A scuffle heard, a gunshot went off, Sherlock cried out, and then the phone went dead.