Chapter one: The true story?

It has been over 70 years since Aang was killed by Azula and Zuko. The fire nation had won the war, and is ruling the world. All hope is lost, or is it? Aang was the last avatar, he died in the avatar state, but for some reason, the fire nation is still trying to find the new avatar. Are they just being paranoid about the avatar defeating them, or should they be worried?