On an island on the edge of an immense sea there is a city, a forest, and a boy. The city is called Asteri, a perfect city that was saved by the magic woven into its walls from a devastating plague that swept through the world over a hundred years before. The forest is called the Barrow, a vast wood of ancient trees that encircles the city and feeds the earth with magic. And the boy is called Oscar, a shop boy for the most powerful magician in the Barrow. Oscar spends his days in a small room in the dark cellar of his master's shop, grinding herbs and dreaming of the wizards who once lived on the island generations ago. Oscar's world is small, but he likes it that way. The real world is vast, strange, and unpredictable. And Oscar does not quite fit in it. But it's been a long time since anyone who could call himself a wizard walked the world, and now that world is changing. Children in the city are falling ill, and something sinister lurks in the forest. Oscar has long been content to stay in his small room in the cellar, comforted in the knowledge that the magic that flows from the trees will keep his island safe. Now, even magic may not be enough to save it.