14-year-old Caspar Fransson moves with his family to the small town of Thorville. Caspar is really tired of having to move and changing schools, due to his mother’s foolish archaeological assignments. But nothing turns out as he expected in Thorville. The first day in school, Caspar meets the mysterious girl Magda. She claims that he has come to Thorville to help her search for her missing father, but Caspar would rather be left alone. Still, he starts to help her in her search, reluctantly, at first. Inexplicable things happen, and clues lead them to a sunken Viking ship. All of a sudden, Caspar realizes that he is part of a strange and marvellous puzzle; a fateful life-and-death adventure.