Luna guards the night. She protects everyponies dreams and dispells any wandering nightmares. But she is startled when she spots a sleepless pony playing amongst the fireflies at night. A young mare trying to deal with her parents' tragic death finds herself in Ponyville. She intends to spend the rest of her days, and nights among the friendly fireflies, trying to forget the tragedy, but the princess of night has a brighter future in mind for the young mare.