Petty bootleggers Carlo Baggio and his brother Jake are enjoying the good life in 1925 Prohibition Chicago until Carlo enters into an arranged marriage with a bride from Italy and Jake gets run out of town for cheating on the boss’s daughter. In the aftermath Carlo takes a bullet for Jake and is ready to cash in his chips until a black angel Carlo dubs Angelo Nero convinces him otherwise. Later Angelo Nero comes to Carlo’s rescue when he’s trapped in a house fire. For the next fifty years the Baggio brothers and their families will experience hardship, tragedy, rewards, and the unwelcomed honor of Carlo’s son becoming a priest.

When Angelo Nero finally returns, it is to visit Carlo’s grandson Frank, the only survivor of a multi-fatality accident. The life-altering experience prompts Frank to follow his uncle into the priesthood. Eventually, with help from the uncle, Frank winds up in Rome, training for the prestigious Vatican Diplomatic Corps. He encounters the angel again, along with a mysterious warning. Later, while awaiting his first post, Frank becomes involved with a secret society within the Vatican that assigns him the task of delivering a renegade-priest to Romepreferably laid out in a coffin. Frank’s covert mission brings him back to the family farm in Illinois and to his grandfather Carlo. Angelo Nero shows up too. But neither Carlo nor the angel can help Frank choose between the diplomatic career he has coveted for years or sparing the life of a priest defying Catholic tradition.