The series centers on a murder committed by the leader of a sect called "El Arca", which was founded in the nineties in a distant village. One day, Olivia, a young assistant to a Spanish prosecutor, is assigned the task of investigating a police case in that same town, where some time before the death of her mother occurred. During her stay, she meets Román, a young local who knows the community better than anyone else and joins her to uncover the truth behind the heinous crimes that plague the inhabitants..