The boy in the iceberg

Four elements: Water, Earth, Fire, Air.
An Avatar. The master of all elements.
Only one each lifetime.

But what if there were two?

Aang spent 100 years frozen in ice after trying to escape his destiny leaving the fire nation to conquer the world. When all hope seems lost the spirits chose to birth an avatar. A girl. To bring balance back to the world.

But she doesn't know. No one does until banishment with her Prince pushes her into directions she never even dreamed of.

what will happen when the two avatars meet? what will happen when zuko finds out an avatar has been with him the entire time.