Welcome to the island of the Ys, a piece of land lost somewhere between the Real World and the Unsure World. On the Ys, children go to school and play games just like other children . But they also live among knights and wizards who protect them from the dark forces of the Unsure World — a place where bandits, giants, and monstrous creatures live on a treacherous landscape. On the Ys lives is a twelve-year-old boy named Guillemot de Troil, who dreams of becoming a knight. Guillemot lives with his mother, his father having mysteriously disappeared years ago. The first book in this adventure saga introduces us to Robin, a boy who lives on the Lost Isle of Ys. One night, Robin's potential for magic is revealed in the presence of Quadehar the Sorcerer. Robin becomes the sorcerer's apprentice and studies the magical secrets of the craft. His talents are put to the test when he and his friends must cross into the Uncertain World to save a classmate who's been kidnapped by monsters. Will Robin's newfound knowledge help them prevail?