A beautiful young woman covered in blood, who claims to be an ancient prophet in search of a mystical amulet, has been arrested in the streets of Rome. Ex-priest Tom Shaman teams up with a headstrong policewoman to unravel the mystery. But within Rome’s churches and corridors of power, stealthy enemies are conspiring against them. And soon, the woman’s deadly visions begin to come true.

A brutal killer is on the loose, and ex-priest Tom Shaman finds himself in the midst of a series of ritualistic killings unlike anything Venice has ever seen. Enlisted by the Italian police, Tom teams up with young investigator Valentina Morassi to dig deep into the city's darkest history. As Valentina and Tom trace the killings through the centuries, they uncover a deadly secret that generations have killed to protect: a priceless mosaic known as the Gates of Hell.

The death of a well-known treasure hunter and archaeologist causes grief for his estranged son, but also sets in motion an ancient prophecy that could unlock the secrets of Stonehenge. Cryptic letters and blood sacrifices are just the beginning.