A/N: Hi! So, I know I'm not the only one who thinks Colin Morgan could be Benedict Cumberbatch's little brother! But I wanted to take my own shot at writing this. BECAUSE GUYS: HOW CUTE?! Anyhow, this is obviously a crossover of BBC Merlin and Sherlock. I think it will be probably more Sherlock than Merlin, and I don't know if I'll put other Merlin characters in this... But basic premise? Merlin Holmes, my friends. I'm excited. I also may get some Doctor Who in there in later chapters, because that would just be awesome! Oh, and this is my first foray into writing for Sherlock, so sorry if it's a bit OOC... Please review! I'd love some feedback! :D Oh, and sorry about the lame title. Please comment in a review if you have a better one?

Disclaimer: I do not own Merlin or Sherlock, (or even Doctor Who) unfortunately. If I did, things would get pretty strange... I am but a humble fangirl.

Thanks for reading!

John Watson walked in through the door to 221B Baker Street looking irritated, just as he always did after a trip to get groceries. "Sherlock!" he called, "I'm back!"

He didn't expect Sherlock to answer. His flat mate was probably waiting for him to let him borrow his phone, or pass him a pen, or something, but he wasn't exactly the type to welcome you home.

That's why the next events came as such a surprise.

There was a loud crash, and then a horrified gasp, and then Sherlock came sprinting through the flat to the door to meet him, looking surprisingly frazzled for such a usually…inhuman person. "Ah… John, glad to see you're back!" Sherlock gasped.

John sighed. "You too, I suppose. I got the groceries…" he held up the bag to show him. "Now what on Earth is going on in here?"

Sherlock stiffened. "…Nothing, John. Don't be ridiculous."

"What did you do, Sherlock? I may not be a genius, but it hardly takes one to know that you're lying." John said, shaking his head. "Don't tell me… Some sort of battle, that'd explain the crash… Or did you just get bored again?"

Sherlock looked nervously over his shoulder. "Did you get the tea, John?"

"We have plenty. You're not distracting me."

Sherlock gave him a pleading look. "John…"

"Come on then, I live here too. You at least owe me an explanation!" John cried, getting quickly fed up with his childish flat-mate.

"I live here too, and I can at least have some secrets, can't I?" Sherlock snapped back.

John glared at him. "Let me think about it… NO. You cannot! Your secrets usually involve near death experiences and a lot of trouble. Don't make me call Mycroft!"

There was a loud scraping noise upstairs.

"What was that?" John asked.

"Uh… nothing. You were saying?" Sherlock responded quickly, glancing unconsciously towards the noise.

"Sherlock… I have never seen you so jumpy before. EVER! What is going on?!" John yelled.

Sherlock shrugged. "It's… really nothing. Just… a rat."

"That is the most unbelievable lie you have ever told. Something's wrong." John pointed out, walking past him towards the stairs.

"Of course, now you'd choose to not be an idiot." Sherlock muttered irritably as he followed him.

"Guess you're rubbing off on me then," John sighed.

Sherlock smirked, crossing in front of him at the top of the stairs. "Fine. I guess it will be easier this way."

John looked confused. "Sherlock, what…?"

"Come on out, then, he's a friend!" Sherlock called.

The door peeked open, and out stepped a young man John had never seen before. He reminded him of someone, with his pale skin, high cheekbones, and dark hair… Even if it was straight instead of curly behind his oversized ears and his eyes were a darker blue than he was used to...

Sherlock gave a weak smile at John's shocked expression. "John, meet my little brother, Merlin Holmes."