During one summer day, Celestia is asked to watch after her sister, while their mother is gone for certain duties. Celestia thinks, this task won't be diffcult at all, but she is completeley wrong. Especially because she loses her sister within the first few hours.
Luna is walking into the Everfree Forest and bumps into a dark mare. This mare, Nightmare Moon, is searching for a host and she definitley had not looked for a cub. But because filly Luna does not want to leave her alone, "Moonie" has to play babysitter within the Everfree Forest.