This is a Superwholock fanfic! I do not own anything from any of these shows!
"C'mon we really need to take a break, why don't we take a trip to London or something... We can bring Cas too if you want." Sam had been begging Dean to go to London for weeks but the Sam reply was always a strict no, but this time Dean's reply was different, "Fine, we can go to London and we are bringing Cas thank you very much!" Sam murmured to himself, "Of course you said that cause he's like your angel angel boyfriend!" he chuckled as he got out his laptop and reserved the cheapest motel in London, it was an extra room right around 221 baker street.
They got into a plane after not being allowed to take their weapons besides a couple of silver knifes that were in their bags. Dean was utterly terrified and knocked himself out by drugging his drink. They decided they would call Castiel once they had gotten to their hotel and had everything else planned out.
They finally arrived, Sam woke Dean and they were off to a diner or some cafe at least. They had there luggage and were walking down the road when suddenly, "Doctor! Doctor! Get back here!" A tall curly black haired man in a black trench coat yelled furiously while running after a man and girl. The man had something in his hand, it didn't look like anything they've seen Dean thought it was some kind of robotic dildo. They watched as the tall black haired man slowly got farther away when they noticed that he was looking at them, "Winchesters!?" They were in shock after hearing that from the man's mouth, Who is this guy? How does he know us? Also, doctor? Doctor who? Sam and Dean were both thinking the same thoughts. The man suddenly forgot about "the doctor" and ran across the street to them, "Who are you and how do you know us!?" Dean was the first to speak.
"I'm sorry, Castiel must have not told you about me, I'm Sherlock... Sherlock Holmes." Sam's eyes widened, "T-The Sherlock Holmes!? But you're a fictional character in mystery books!" Sam held out his hand and Sherlock shook it. "Yes I know that... But you notice how I do not have John with me and I was running after that Doctor? Well, that man is a time and space traveler, he managed to go through the cracks in the universe and he brought me here... Sadly John did not come along and the uh cracks have closed sealing all of them here with us..." Dean and Sam were confused, "Sorry Sherlock but who is with us exactly and should we get Cas out here!?"
All of a sudden a sound of wings came from further down the sidewalk followed by the sound of someone running, "Sherlock! What are you doing here!? I thought you swore to John you'd never leave again!" Castiel shouted until he finally had stopped standing besides Dean. "I know, I came with the Doctor... The-The cracks have closed and um well... I'm very sorry my dear little angel." Castiel's eyes filled with worry as he leaned closer to Sherlock, "What happened? Is it Moriarty is he here as well Sherlock?" Sherlock nodded as he looked away, the Winchester's both confused out of their minds. "Do you mind explaining all of this Cas?" Castiel snapped out of his sorrow for Sherlock and nodded, "Yes I will but let's go ahead and get to the hotel." They started walking down the road forgetting everything as they tried to wrap their heads around what was going on.
It was around 8 at night where they were, Sam just wanted to fall onto the bed and sleep but he knew that whatever was happening they would have to help and they need to know all the details. Dean and Sam sat at the foot of their beds as Castiel and Sherlock stood in front of them. Sherlock looked to Castiel as he spoke, "Okay, now you already know this is Sherlock, well we met when I was universe jumping... I suddenly found myself in the universe where the stories of Sherlock Holmes existed but the books did not. Then I ended up bumbing into Sherlock and John and we solved a couple crimes until eventually I remembered that your prayers can't get to me in this universe and so I returned... Sherlock may tell you the rest." Sherlock cleared his voice and took a nearby chair and sat in it backwards looking at the Winchesters.
"After Castiel left John and I continued on with our lives until eventually I found a peculiar blue box from the 1980's... Those haven't been anywhere in England for the past 10 years, so I found a key, opened it... It ended up being some sort of ship, a few moments later a man had burst through the doors and started doing things with the mechanics not knowing i was there until after we had somehow gotten to this universe... He told me who he was and what happened, I told him to take me back but he rejected leaving me here never to see John again." Dean didn't understand any of it, spaceships? Blue box? Does this guy need to go to the loony bin!? Castiel paced back and forth until he finally stopped looking out the window, "Then how did Moriarty and the Master get here? And how do we get rid of them, don't forget that I can jump univers- wait... The cracks closed!?"
Sherlock nodded and stood up, "What's wrong Castiel can't you just take Moriarty and me back?! Can you not!?" Castiel was silent, "Answer me you winged rat!" Sherlock yelled at Castiel furiously, his eyes began to tear up. Dean watching the whole scene like it's some sort of drama TV show. Sam stood up from the bed, "Sherlock!" He walked over to him, "I understand how you're feeling, you have left your world and your best friend John, but we will find a way... We will get this Doctor and make him tell us how to open those cracks and how to get you back to your universe or how to at least get John here! Just please calm down!" He sat back down on the bed and watched Sherlock as he took deep breaths trying to get a hold of himself.
"You all should get a good nights sleep, I will stay here just in case something happens. Sherlock you may stay as well there is a couch in the other room." Castiel turned to all of them and pointed to the room in which the couch was. Sherlock put the chair back and went to the couch immediately still having aggression with each movement. The brothers lied in there bed and fell asleep quickly hoping the next day would be less catastrophic.