This is an avatar the last airbender and Percy Jackson crossover. The idea is Posiodion want's Percy to have a better life away from the gods so he sends him to a different world. The avatar world. Only problem is an incredibly powerful half god being thrown into the middle of a 100 year war can cause some problems.

Percy and Annabeth get sucked into a black hole, sending them back in time into their 12 year old selves.

The ancient world was a harsh and unforgiving place. Alone and without family, a child has almost no hope of survival. But the life of a demigod is almost always full of surprises. Unlikely friends and dangerous enemies often change destinies. With a little luck and the grace of the gods, what could have been ordinary can quickly become extraordinary.

Percy, a name a boy took when all he knew was war. When he learned the name from a close friend he took it as his own so he could be a Hero. However years passed and that dream became naught but an old relic, just like the hero himself. Due to circumstances, he is forced apart from his family. Having to walk his own path, he finds friends and family to call his own once again. But will his past come to haunt him? Or will a special someone deliver him from death?