Hi again peoples of the internet! This is my first attempt at a crossovery type fanfic so yeah... Lots of the credit for this idea goes to Lulu Bee! It basically came from some crazy theories and a bout of wild fangirling at Sherlock club (yes my school does have that!) But yeah, please enjoy! Reviews are very welcome, i'd love to know what you think. Any suggestions are also very welcome too! I need an animal guide for the avatar and an element he struggled with... love you all xxx :D

It was a slow day at 221B Baker Street. Sherlock and John were between cases and Sherlock had turned away all potential cases that day because they were too boring. Yet, for some reason he seemed on edge. After a lot of pacing, muttering, spontaneous violin tunes and shots fired at the wall he turned to John and said in deadly serious tone, "John, there's something important I need to tell you. I haven't been completely honest with you."

Oh god, thought John. Is he going to admit he has feelings for me? Not that that would be such a terrible thing...

But no. Sherlock handed him a pile of DVD box-sets, told him to watch and learn and said he'd be back later. And with that he left the flat.

May as well, thought John. He sat down on the sofa and watched his way through all 3 seasons of the last airbender and 2 seasons of the legend of Korra. Just over 24 hours later, when he'd got to the end he turned around and saw Sherlock sitting and watching him.

"What did you think?" asked Sherlock.

"Well..." replied John."I loved it! That was so good! Parts of it were so funny and then parts of it were so sad, and I know it's ridiculous to want to cry at a cartoon but I did! It was so frigging epical, but it had to end didn't it? God, I wish it were real!"

Sherlock stared at him for several minutes before saying, "Who ever said it wasn't."

"I'm sorry, what?" John was confused. "It's a kids TV show. How could it possibly be real, and how could you know about it?"

"Because John, I know lots of things that you don't. That TV show is heavily based on history. History that has been altered by the world's government, to hide the truth. And fine, not every aspect of that cartoon is accurate, but it is a cartoon. And the reason it tells the truth is to throw people off the scent. Most children who watch it believe it to be fantasy. They wish it were real, but know that it isn't. At least the world is telling them it isn't, but they're all wrong.

From the end of Aang's hundred year war onwards the amount of people born with bending abilities was decreasing, and has kept decreasing slightly ever since. Added to that the amount of people which had their bending taken in Korra's time and there aren't many left. There wound up being so few, less than 100 in the whole world, that the entire history was covered up and dismissed as a fantasy to protect these individuals. You can imagine how people would want to exploit these powers.

Republic City is gone now, but it existed. It looks like the 1920s because it was. There are quite a few elderly people around with modified memories from after the cover up. But the few remaining benders are still around if you know where to look. And the avatar cycle has not been broken. Korra lived to be 70 so an earthbender born around 1980 would fit the equation. And the time is coming for them to restore balance to the world once more."

"Sherlock. You are talking nonsense. How could that even be possible? And how would you know all that information?"

"Because of The Earthbender. The one that fits the equation. I'm him. He's me. John, I'm the avatar."