Traveling on a ferry heading to the island of Hierro where they will spend their holidays, Mary loses her son Diego, and no one can explain what happened. Six months later, Maria struggles to overcome the pain of loss and continue his life. Then, you receive an unexpected phone call: they found the body of a child, so it must return to the island. There, in the suggestive and disturbing landscape, surrounded by disturbing and sinister characters, Mary is forced to confront their worst nightmares. And as he travels this road, he discovers that some mysteries should not be disclosed …