The world this book is set in is intriguing by its combination of fantasy and advanced technology. The main character, Ana, is vividly portrayed as an overly defensive yet headstrong teenager who's seeking her identity. Her growing affection for her protector Sam is delicately written as well.
Those are the elements that keeps the reader in the story, rather than its plot which dawdles around Ana exploration of the city of Heart and its politics, history, and its people, none of which ever becomes deeply enriched despite the chapters dedicated to it. Only when dragons threaten the city does the novel rise to its feet.