A royal errand brings Ruskin, Cinder, and Groth to Shadow Hills, home to the most mysterious creatures in all of Wrenly - the shadow dragons. Legend says that shadow dragons are hostile to outsiders and cannot be trusted. In fact, nothing is quite as it seems in Shadow Hills. The young dragons have been sent there by sinister forces that believe Ruskin is destined to rule over all of Wrenly. These same forces will do anything to prevent that from happening, even if it means putting the entire kingdom at risk. Will Ruskin and his friends see through the deception and learn who they can really trust?