In Italy, the Cardinal Vicar of Rome is assassinated during a papal celebration. In Los Angeles, entertainment lawyer Harry Addison receives a desperate message from his long-estranged brother, Father Daniel Addison, a Vatican priest. Hours later a tour bus with Father Daniel aboard explodes on the road to Assisi.

When Harry arrives in Italy to claim his brother's body, he discovers that not only may Father Daniel still be alive, but he is the prime suspect in the murder of the Cardinal Vicar. In a sudden turn, Harry finds himself framed for the murder of an Italian policeman. Now on the run and on his brother's trail, Harry is thrust into a terrifying world of horror and deception where an international terrorist hunts Father Daniel as relentlessly as the authorities...and where a monstrous conspiracy arises from the very heart of the Vatican.