Perseus Jackson was not the son of Poseidon. Instead, he was the firstborn son of Jade Emperor and his wife Wangmu Niangniang. When his father senses the rise of his demonic enemies, he sends his son to the United States, where he is to gain the trust of the Olympian Gods and bring about peace between the two Parthenon's, and in turn, come together to fight the demon horde that marches against Jade Emperor.
Disclaimer: I don't own Percy Jackson or most characters, Rick Riordan does, or Chinese mythology.
Story is rated PG-13 just in case. Not sure if I am going to have strong language in this story, but if I do then it's already PG-13.