Nyx, a pegasus filly, hates her family. More importantly, she hates the fact that they're all unicorns. And most specific, she hates the fact that they hate her. And she knows it. Her parents love 'precious little twilight' more than her. And her big brother isn't even here anymore to say anything. So right after Twilight gets accepted as Celestia's student, she hits the road and lives life as an orphan. Which has a larger impact on her life than she thought it would. Let's just say it's as big as the moon is.