An attempt to sever the connection between Corakinus and April inadvertently strengthens their bond, causing her to manifest Shadow Kin traits even as she deals with the release of her father, Huw, from prison. Miss Quill discovers that Charlie has been lying to her about the Cabinet of Souls, driving her into the orbit of Coal Hill's new headmistress, Dorothea Ames. Acting on behalf of the mysterious Governors, Dorothea offers Miss Quill a way to free herself from her thralldom... but first, London must survive an invasion by carnivorous flower petals.