This is one of the books for young people that Zafon wrote before moving into adult fiction. The story is set in Calcutta in the 1930s and follows the fortunes of a group of youngsters recently leaving an orphanage as they battle with some dark forces.
Zafon is excellent in his atmospheric writing and is a splendid master of language. Though my Spanish is not completely fluent I could appreciate his talent and enjoy the story.
If you enjoy this, try "La Sombra del Viento", his very successful book for adults.