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.

Inspired by a true story, Evelia, a Mexican migrant, becomes the only witness to the murders of the mysterious family she works for. She must make the decision of her life if she is to survive.