Sherlock Holmes across the multiverse

Chapter 1. Baker Street London

The air in London was chilly but not too cold yet the air was carrying the familiar smell of coal smoke and the distant rattle of horse-drawn carriages on cobblestone streets. It was a typical morning in London at 221B Baker Street. Dr. John Watson sat comfortably in his chair by the window, sipping his tea while glancing through the latest edition of The Times. Sherlock Holmes, ever restless, was pacing in the middle of the room, deep in thought.
"Something's not right, John," Holmes said abruptly, breaking the silence.
John folded his paper. "Isn't it this way always?"
Holmes gave him a quick glance, but before he could respond, the door to their apartment was burst open. Mrs. Hudson, their landlady, stood in the doorway with her eyes wide open.
"Sherlock, you've got visitors, quite strange visitors, if I'm being honest," she said, her voice sounding slightly confused.
Holmes raised an eyebrow. Bring them in."
After a moment, two men stepped into the room. The first guy was rough, with a hardened look about him, his hair was cut short and his eyes was scanning the place and surroundings with military precision. He wore a leather jacket, but the most noticeable thing about him was his left arm,i t was made of metal and it was glistening under the natural sunlight light coming through the window. The second man had a more natural look, he was wearing a fine suit with an exuding aura of confidence. His neatly trimmed goatee and sharp gaze gave him the air of a man who had seen far more things than his appearance suggested.
"Sherlock Holmes" the metal-armed man began, his American accent jarring in the Victorian setting. "We need your help."
Sherlock remained silent for a moment, his eyes darting from one man to the other, taking in every detail. "And who are you?"
"James Buchanan Barnes,but I usually go by Bucky" said the man with the metal arm. "This is Tony Stark."
Holmes tilted his head slightly, curiosity piqued. "Two Americans in London, one with a mechanical arm and the other technology far beyond anything I've seen. Fascinating. So tell me, how did you come to be here?"
Tony Stark, whose eyes had been wandering over to Sherlock's apartment finally spoke. "It's a long story. Let's just say us two are...not from around here."
John furrowed his brow. "Not from London?"
"Not from this time he meant" Barnes clarified, his tone serious.
Holmes paused, his sharp mind already racing to process this unexpected turn of events. " you guys are time travelers?"
Stark smirked. "More like... we got stuck here thanks to some bad guys playing with forces they don't understand."