Santi, a high school student who suffers from a severe sensitivity to sunlight, must relocate with his single mother to a secluded, shadowy village in the Spanish mountains due to his health condition. The villagers soon show themselves to be oddly xenophobic. As horrific and violent incidents start to unfold, Santi finds himself ostracized at school and becomes a prime suspect in a series of gruesome murders. Despite this, Santi fears that he might actually be the next target.