Nightmare Moon

The Child of Artemis is a non-canon (duh) story in Rick Riordan's Percy Jackson universe.

Sophia is and orphan coming up on her thirteenth birthday. All she knew about her heritage is that her father came from a long line of poor people that gave all that they had to weary travelers. All of her problems at the West Anderson Orphanage are suddenly washed away on the eve of her thirteenth, when flying horses eclipsed the moon.