A/N: First off, I want to apologize how long it took me to write up another chapter. With Reichenbach and my birthday, I've been famished.

If you haven't realized already, this is the Epilogue.

I've enjoyed writing this, and the next time I write a Sherlock/Doctor Who crossover I hope you'll tag along :)

Thank you so much for all of the reviews and favorites. You guys make my day when I get an email notifying me of this.

So enjoy!

And review! :)

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They were surrounded.

John couldn't believe this. Actually, he could, which was quite pathetic in a way, but never mind that. The four of them were back-to-back at the moment, all of their gazes fixated upon the creatures surrounding them, holding some sort of weaponry.

They were, in fact, amazing in a way. Certainly not like the merpeople John had seen in movies or paintings. No, these beings were different.

John's eyes assessed the closest one to him. The girl's fish tail was approximately twice her body size and covered in deep blue and purple scales. It slowly swayed through the water, sort of mesmerizing. Her skin was milky white, the palest he had ever seen, and her light blonde hair made her seem even paler. With a startled jump, John looked at her eyes and saw they were black. Not dark brown. Black.

"Why have you come here?"

John glanced around and blinked, confused. Where had that thought come from? Or had someone spoken? John's confusion grew when he remembered they were underwater-

His gaze locked onto Sherlock's and he raised a brow, silently questioning him. Sherlock gave him 'that' look, then raised his slender fingers to John's forehead, tapping them against it.

Oh. Right.

First a girl who 'comes back to life', a man with a bigger-on-the-inside time-traveling telephone box, merpeople, a new planet, breathing underwater, and now telepathy.

Of course.

Sherlock gave John a small smile, but his attention snapped back to the merpeople once they started to speak again.

"Talk? Why would we need to talk to you, Doctor?"

John glanced to his other side and saw the Doctor staring at one of them – John guessed it had been the one speaking. By the look of the Doctor's facial expression, the ex-army doctor realized he was speaking back to them.

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Amy watched curiously. As of late, she had been close to her raggedy man in a way she knew she hadn't been close to anyone else. He was her best friend and she was his companion.

So the worry lines creasing his forehead, and the tight set of his mouth obviously told her something was wrong. She realized after a few seconds of thinking, that Eleven and the merpeople were telepathically speaking to each other.

What got her curious bumped up a few more notches though – was the fact that they weren't letting her or the other two as far as she could tell, in on the conversation. So it obviously meant that it was something private.

How long had it been since they dove underwater? Ten minutes? Twenty? Now she wondered if they would even need the other gillyweed, time was passing by so slowly.

Her thoughts were confirmed when suddenly, the beautiful merpeople suddenly vanished as quickly as they had come. Amy turned to the Doctor then, questioning him with her eyes. He stared at her for a few moments, a sad look overcoming his features. A quick shake of his head along with an upward point of his finger told her that it was time to go.

…

The ex-army doctor pulled himself up out of the dark water with the strength of his arms, falling onto the rocks. He breathed heavily but the tightness in his chest slowly faded, leaving him with his normal breathing pattern. The gills and fins had vanished from the four of them and now they sat on the wet rocks, drenched.

John cleared his throat. "So what happened down there?"

When no reply came, John looked to Sherlock for an explanation, but all he received was a downward cast of his eyes. The consulting detective knew, no doubt. But for once, he wasn't bursting out pompously with his deductions.

"Doctor?" Amy prodded gently, placing a hand on the man's shoulder.

"The people of this planet…are dying." The Doctor dragged a hand down his face. "To put it simply – the experiments and such were to try and create a new race. One that could live on and flourish. Only one experiment was a success, the rest failed."

John pieced together the facts. The only experiment that had lived was the one that was currently sleeping in the Tardis. Without a mate, though, John guessed that their plan wouldn't quite work out to their liking.

A moment of revered silence passed between the four of them before the Doctor stood up. He locked eyes with Sherlock. "Case solved, then, I assume?"

Sherlock gave a curt nod. "Case solved."

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John stepped out of the Tardis and was met with the air of London and a welcoming sense of home. The consulting detective followed suit, along with the Doctor and his companion. The dark clouds hanging above the city did no help to their saddened mood and thoughts.

The Doctor held out his hand to Sherlock. "Your insight helped, thank you."

The raven-haired man stared at him for a moment before shaking his hand in return. "It was enjoyable despite the outcome. What will you do with the girl?"

"I'm going to take her wherever she pleases. I'm not sure if she'll want to stay on her own planet – it could be slightly depressing." He smiled sadly.

Sherlock nodded slowly, agreeing.

The Doctor then turned to John, a smile on his lips. "Goodbye, John. I have a feeling this isn't the last we'll see of you."

"What do you mean-"

The Doctor grinned, spinning around to face the Tardis. "Come along, Pond! I know of this wonderful planet right beside…" His words faded as he disappeared into the telephone box.

Amy laughed and shook her head. She smiled at John. "I'm sure we'll see more of each other soon. The Doctor never leaves someone's life, not really." Her eyes flickered to Sherlock, who was walking away down the road. "Keep a close eye on him. I can sense that he depends on you more than you think."

John glanced behind him incredulously. "What, Sherlock does?"

Amy gave him a quick and warm hug. "More than you think." She simply repeated. "Goodbye, John."

And with those last words, Amy skipped through the Tardis doors and they shut behind her with a snap. John watched curiously as the blue telephone box slowly disappeared until nothing was there.

The ex-army doctor caught up to his flat mate and gave a long, dramatic sigh. "If I hear the word 'bored' come out of your mouth over the span of the next few days, I will punch a wall."

"That would be quite entertaining to see, my dear Watson."

John just laughed and shook his head. "Do you think we will really see those two again?" He looked at Sherlock.

"I'm positively sure we will. Now, how are we going to explain this to Lestrade?"

Sherlock smiled as John burst into a fit of giggles.

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And all four of them realized then, truly realized, that their lives were anything but simple.