15 years before the lightning thief, Artemis broke her oath. She was humiliated and did not want anyone to find out. She decided to kill the father and the baby, but Artemis didn't want to kill the child, so she abandoned it and left it in New York, giving Dionysus a hint as to where it would be. Apollo felt terrible for the boy and his sister's cruel actions and let the boy stay in his cabin. Years later, a new kid arrived with a minotaur horn and he has to supervise him. All credits besides Orion go to Rick Riordan (An absolute Legend)