Santi, a young high-school student with a serious physical reaction to sunlight, is forced by his health to move with his single mother to a shadowy, isolated village in the mountains of Spain where the inhabitants begin to reveal themselves as strangely xenophobic. When terrible, violent events begin to occur, Santi becomes first a pariah at school and then strongly suspected by the police of hideous murders. Santi himself, however, wonders if he is not the next victim.

After losing his father, 10-year-old Carlos arrives at the Santa Lucia School, which shelters orphans of the Republican militia and politicians, and is taken in by the steely headmistress, Carmen, and the kindly professor, Casares. Soon after his arrival, Carlos has a run-in with the violent caretaker, Jacinto. Gradually, Carlos uncovers the secrets of the school, including the youthful ghost that wanders the grounds.