Twelve years after the death of his father in the Valley of Lotar, Pablo Galván receives a letter that his father Arturo wrote to him shortly before dying. The letter asks him to return to the valley to investigate a medieval legend related to the mythical reign of Leonis. When he gets to Lotar, Pablo is reunited with his childhood sweetheart, and discovers that his father's death remains an unsolved mystery, one more in a chain of strange events that have been occurring in the valley for centuries. As he investigates his father's dark past, Pablo becomes drawn into an ancient ritual that will lead him to a fate as imposible as it is inescapable.