The film tells the story of how, in post-war Spain, Narcisa (played by Aria Bedmar), a novice with supernatural powers, arrives at a former convent, now a school for girls, to become a teacher. As the days go by, the strange events and increasingly disturbing situations that torment her will eventually lead her to uncover the terrible web of secrets that surround the convent and haunt its inhabitants.

双警探被迫重启六年前未结悬案，在史前人类洞穴的献祭仪式与现代财阀的石油黑幕间，与重出江湖的连环杀手展开「文明进化论」式生死博弈——当少女尸骸上的尼安德特人齿痕，指向一场跨越万年的道德崩坏