A teenage boy who suffers from acute sensitivity to sunlight becomes the prime suspect in a horrific murder case after moving to a small village located in the mountainous region of northern Spain. Santi is a 16-year-old boy who lives in Barcelona with his mother, Julia. But while most folks who live in Barcelona love to bask in the golden rays of the sun, Santi has a rare genetic disease that causes him to suffer severe sunburn and eye irritation within minutes of exposure to ultraviolet light. Ideally, Santi would like to move to the shadowed town of Laponia in northern Sweden, but funds are tight and his mother cannot afford to make such a move. After a heartfelt discussion between mother and son, Julia agrees to move to Arrozas de Valdeon -- a remote village shaded by the high mountains on all sides. But strange things are happening in Arrozas de Valdeon; animals are disappearing, and rumors are circulating that something in the woods is responsible. One day, Santi witnesses the killing of a young boy. No one else was around at the time the murder occurred, making Santi the prime suspect in the eyes of the villagers. In order to avoid any further problems, local policeman Antonio asks Julia to keep an especially tight leash on Santi as an investigation gets under way. But Santi is determined to prove his innocence, and after making friends with a local girl named Angela, the pair sets out to locate the mysterious creature rumored to stalk the local woods. What Santi and Angela discover over the course of their investigation can only be described as tragic.