When Twilight Sparkle manages to get a hold of The Legend of Nightmares, and learns exactly what and who they are. With many questions already, Twilight and her friends must figure out just what these beings want if they want to stop them from overthrowing Celestia and Luna, and waging a new war on Equestria. Three books are left to Twilight when their leaders must remain silent; The Legend of Nightmares, a diary, and a warning.