While Lenny Belardo begins his pontificate as Pius XIII, he calls on Sister Mary, his childhood guardian for help, and begins to familiarize himself with the Vatican.

Cardinal Voiello continues his investigations, while tensions arise between the Pope and Sister Mary.

In the wake of the Pope's controversial homily, Sister Mary is thrust into the spotlight, and Voiello is determined to discover the Pope's weaknesses.

As Voiello continues his secret campaign against the Pope, he manipulates another into joining his plot, while the Pope himself reveals radical new plans for the Church.

The Pope takes an unscheduled trip away from the Vatican, Voiello has a crisis of conscience, and the Cardinals are finally given their audience with the pontiff.