at a loss after finishing their endofyear exams aubrey and george travel to the gallian capital lutetia where it so happens that the lovely caroline is studying natural history aubrey wants to pursue a cure for his condition though his family have other ideas and hes soon burdened with a royal mystery to solve old letters to procure a missing ornithologist to locate and a spot of diplomatic espionage these tasks should keep aubrey occupied but that would be underestimating aubreys sense of curiosity and uncanny knack of being in the wrong place at the wrong time someone is stealing peoples souls and turning them into mindless monsters and the countrys magical lifeline the heart of gold has been stolen leaving the city in chaos aubrey george and a somewhat reluctant caroline are on the case