A woman's disappearance hides a terrible truth. After years of lies, a dark secret emerges-not seeking justice, but demanding revenge.

Only when a series of murders begins to interfere with the investigation does he realize that he is not the only one interested in the case. Hidden in the shadows is the serial killer who is terrorizing the city of Rome. And it is he who is pulling the strings of the game.

The media have nicknamed him "The Missionary" because of the signature that distinguishes the macabre crimes: a blood cross on the victims' foreheads and a Bible verse inside the corpses.

For Nardi, the challenge with the killer will soon become personal. He has no idea what motives drive the perpetrator to kill, but he knows for certain that if he wants to outsmart him and prevent more bloodshed, he must quickly discover the invisible thread that connects him to his case.