Demi-Wizard Percy Jackson

DISCLAIMER: I DO NOT OWN PERCY JACKSON (RICK RIORDAN) OR HARRY POTTER (J.K ROWLING).
Ten-year-old Percy Jackson is an orphan. On his eleventh birthday, Poseidon visited him, telling him to go to Britain and meet his God Brother Harry. He attends Hogwarts and meets Harry at King's Cross.
He doesn't know about Harry's fame, but notices his own rising at Hogwarts.
He was told that a certain stone needs to be lead to Harry.
Hermione grows suspicious of his activities at night. Who swims at the lake? Why is Percy so attached to it?
Will Percy survive Hogwarts before he reaches Camp Halfblood?