You were walking around Goode High with your best---but weird friend---Grover Underwood. It was a peaceful day until he eventually told you the truth after you guys encountered a Fury, who used to be your science teacher.

Once you killed it---or vaporized it---he told you how you're a Demigod. Or in other words, a Half-Blood of mortal and God/Goddess. And how he's a Satyr. It would explain the way he walked. But with that information. He took you to Camp Half-Blood that same summer and day after school.