Twilight and Spike join Star Swirl's daughter Nyx in exploring the worlds Star Swirl created to teach key principles of Writing and find themselves in the last chapter of a madpony's tale of betrayal, revenge, and restitution.

Three months after their original adventure in Aitran, Twilight and Rainbow receive a letter from Star Swirl requesting their help. He sends them into the world of Sohndar on a mission to find his wife and daughter and capture an old enemy of his.

Twilight Sparkle discovers a strange book in the Canterlot Archives that transports her and Rainbow Dash to a strange island. With no obvious way home and few clues, they set out to unravel the mysteries of Aitran, its hidden books, and its creator.