In Milan, Khalidà realizes that she is a burden for Augustine's career and decides to distance herself from him and his beloved son. The excruciating separation from Khalidà, the relationship with Bishop Ambrose and the discovery of the hypocrisies of court life aroused in Augustine an ever more acute torment, until he witnessed, helplessly, at the charge of the empress's guards against the Catholic faithful, among whom he also recognizes his mother. His crisis comes to a head. After a night of anguish and remorse he hears the famous phrase: "Take and read ..." and, in a passage from San Paolo, he finds the electrocution and under the moved eyes of his mother he is baptized by Bishop Ambrose. Soon Monica will die shortly before returning to Tagaste.
Years after his conversion, Augustine became bishop of Hippo. In this capacity he convinces the head of the heretical Donatist bishops to call a council to put an end to the "fratricidal" conflict between them and the Catholics. The Donatist bishop accepts only on condition that the dispute is arbitrated by Judge Hilary, an incorruptible man of proven honesty. The council ends with the victory for the Catholics but it will cost Hilary the death, killed by a Donatist hand. Only now do we discover that the son of Hilary is Fabius, the same Fabius who is now in Hippo alongside the imperial tribune Valerius, opposing Bishop Augustine's exhortation to peace. Valerius has gone from words to deeds: he has placed himself at the head of a group of armed men who will attempt a sortie against Genseric's troops who are besieging the city. Before leaving, Fabius says a passionate farewell to Lucilla.
The expedition turns out to be a total failure: the Vandals catapult into the city bags full of the heads of some of Hippo's soldiers taken prisoner. Lucilla is shocked at the thought of having lost Fabius forever. Augustine decides to make a last desperate attempt and, risking his own life, goes to Genseric. Against all odds, he manages to obtain the prisoners' freedom in exchange for the surrender of the city. Despite this, many citizens prefer to rely on Valerius and wait for the arrival of the Roman fleet. However, Augustine decides to stay in Hippo and orders that the cases of his books be disembarked from the papal ship to make room for those who choose to leave the city. Among these, also Lucilla and Fabius, whom Augustine unites in marriage before leaving. That same evening the Roman fleet is completely defeated and the Vandals invade Hippo, while on the burning walls of the city that God has entrusted to him Augustine sees the papal ship departing, with his fellow citizens in safety.
Months later, in the ruins of Hippo, we see a child enter the bishop's ransacked study and begin leafing through one of his books. Today the Vandal army no longer exists. The Roman Empire is just a memory. But Augustine's books are read all over the world.
