She was disowned by her family a few years after finishing her magical education because she had fallen pregnant, by who they assumed was a No-Maj man. Sally never said otherwise.

When Percy turned 11 he attended his first year at Ilvermorny School of Witchcraft and Wizardry. During summer vacation he was attacked by a Fury, and his mother was seemingly killed by the Minotaur as they flee towards Camp Half Blood, a safe haven for demigods.

There he found out that his father wasn’t some random No-Maj, but rather Poseidon, god of the seas. He also found out that Zeus believed that he had stolen the Master Bolt, and that he had to go on a quest to return it to Olympus before the gods go to civil war.