In the kingdom of Bamarre, two sisters could not be more different. Brave and adventurous Princess Meryl dreams of fighting monsters, while shy Princess Addie is content with her embroidery and books. When the Gray Death, a deadly plague, strikes Meryl, Addie must find the courage she never knew she had. Armed only with a magical spyglass and a book of legends, Addie embarks on a perilous quest to find a cure, facing specters, dragons, and her own deepest fears to save her beloved sister.