After saving the King of Sunkland, reuniting the thirteen clans of the Equestrian Kingdom, and defeating the High Priestess of the Chaos Serpents, Mia has finally returned to Saint-Noel for some much-needed respite...until her break gets interrupted by two girls magically appearing before her. Not only is Bel somehow back, Mia must now also care for the mysterious Patricia. Neither Bel nor Mia have any idea where she came from, and the only clue they have is her last name: Clausius.