Princess Luna is worried that Nightmare Moon might escape her grasp again- and her headaches don't help with that matter. This time the elements of harmony won't be there to help- because the nightmare is in her mind. Princess Celestia puts Rainbow Dash in charge of a team of ponies that will infiltrate Luna's mind and defeat Nightmare Moon at the very root- Luna's personality itself. Along with Derpy Hooves, the Doctor, and a surprise guest- will they be able to defeat Nightmare Moon before she re-emerges inside Luna?