Based on Leo Tolstoy's novel, Father Sergius, Night Sun stars Julian Sands as Sergio, a nobleman in 18th-century Italy who is expected to marry a duchess, Nastassja Kinski. Upon learning that she was previously the King's mistress, Sergio turns his back on society and becomes a monk. While at the hermitage he tries to resist all sexual temptations before him and soon becomes known as a miracle worker. Eventually he succumbs to a young seductress and knowing he is undeserving of the adulation, leaves the hermitage to travel around as a homeless beggar.

In the fascist Italy of 1935, a painter trained as a doctor is exiled to a remote region near Eboli. Over time, he learns to appreciate the beauty and wisdom of the peasants, and to overcome his isolation.

Guelfo is a Florentine noble who has never worked and has no money. On the death of his mother, he believes he can inherit a large fortune, but from the notary he learns that he has an illegitimate brother with whom he will have to share half of his inheritance. His brother is called Felice, he works as a waiter in Bari and goes to Florence with a student friend who is indebted to the usurers. A rivalry without quarter begins between the two brothers.

In a forgotten railway outpost, a humble stationmaster meets a glamorous society woman. Their brief wait for her train turns unexpectedly intimate—until her fiancé arrives, and the night erupts into a desperate struggle as he tries to drag her back by force.

Young Franco is imprisoned for murder and rises to become the feared and powerful 'Professor', taking control of Naples' underworld from behind bars.