The adventure begins with a mysterious gift in the form of a crystal received by Michal, a twelve-year-old girl, as an inheritance from her grandfather. Michal concludes that her grandfather left her the starburst-shaped stone as a clue and that clue led to the City of Mystery! Her grandfather had thrilled her with stories of how the City of Mystery held the answers to solving the problems caused by the occupying Tresdids in her beloved city, Salvatore.
Her best friends, Petra (a male unicorn colt), and Flyby (a male golden eaglet) join her, and they all head to the mysterious city. They later meet Zyon, a small purple female dragon, who also adds her expertise to the mission. On the way, they go through dangerous swamps, get lost in spooky forests, and face giant poisonous centipedes, as well as many other escapades. They also have the privilege of meeting the Firsts, the first speaking dragon, eagle, and unicorn, including the first man who was awarded the Blue Orb.
Will the four youngsters make it to the City of Mystery? Will they find the answers they seek?sity.