Sandra Vega, a forensic analyst with the Roman police department, mourns deeply for a marriage that ended too soon. A few months ago, her husband plunged to his death at the top of a high-rise construction site. The police ruled it an accident, but Sandra isn’t buying it. Her eventual investigation is deeply entwined with a series of disappearances that has swept the city, and brings Sandra ever closer to a secret society that will do anything to stay in the shadows.

Six severed arms are discovered, arranged in a mysterious circle and buried in a clearing in the woods. Five of them appear to belong to missing girls between the ages of eight and 18. The sixth is yet to be identified.