In this episode it begins where Twilight Sparkle is reading a book about two sisters.
Princess Luna and Princess Celestia. It says how Luna raised the moon and night sky and Celestia the sun. It says how Luna was jealous of her sister because the ponies played in her light and slept through the night. One day Luna refused to lower the moon and using a last resort Celestia trapped Luna, now Nightmare Moon, in the moon.
1,000 years later Princess Celestia sends Twilight Sparkle to Ponyville to make some friends, but all Twilight wants to do is study. When arriving, she meets one pony who runs off because she hasn't seen Twilight before.