Herod, the superstitious puppet-ruler of the Roman province of Judaea, has married his brother’s wife, Herodias. Soon afterwards, Herod had his brother assassinated. Now he is becoming increasingly obsessed with his step-daughter, Salome.

Reports of these events have brought Herod and Herodias into conflict with the equally obsessive Jokanaan, an ascetic visionary who combines revelations about the arrival of the legendary Judaic Messiah with invectives against Herodias and prophecies of her husband’s death. Imprisoned by Herod in a disused cistern attached to the palace, Jokanaan is guarded by soldiers and observed by a group of wandering Nazarenes, followers of the new Messiah.

As Herod holds a feast, Narraboth, the young Captain of his Guard, stares longingly at Salome and tells Herodias’s page of his obsession with the princess’s beauty. From the cistern Jokanaan is heard proclaiming the coming of his Messiah.

Salome appears, seeking refuge from Herod’s stares. When she hears the voice of Jokanaan she is intrigued. She has heard of the accusations he has made against her mother and knows that Herod fears him. Salome demands to see him. The soldiers tell her that this has been forbidden, but Salome asks Narraboth to fetch Jokanaan.

Salome is enthralled by him. When Jokanaan learns that she is the daughter of Herodias he turns his tirade upon her, urging her to repent and follow the new Messiah. Salome is overwhelmed by Jokanaan and ecstatically praises in turn his body, his hair and his mouth. As both Salome’s protestations and Jokanaan’s denunciations become increasingly desperate, the appalled Narraboth kills himself. Cursing Salome, Jokanaan retreats to his prison.

Herodias, who is also disturbed by Herod’s interest in Salome, emerges from the feast. Herod follows, looking for his step-daughter. Already sensitive to the strange atmosphere of the evening, his discovery of Narraboth’s body increases his foreboding.

Herod’s grotesque advances to Salome are interrupted by the voice of Jokanaan. While Salome retreats ever further into silence, her mother insists Jokanaan be surrendered to the Jews who are demanding he be delivered into their jurisdiction. Jokanaan’s prophecies grow increasingly apocalyptic and Herodias becomes more agitated. Herod, seeking refuge from the encroaching chaos and his own sense of foreboding, asks Salome to dance for him. She refuses. Herod promises to grant her any wish if she will dance. Only when she makes him swear an oath to this does she agree.

After her dance Salome demands as her reward the head of Jokanaan. Horrified and afraid to harm a holy man, Herod offers Salome the most sumptuous gifts if she will change her mind. She, however, is unrelenting. Finally, Herod allows Jokanaan to be beheaded.

With the head of Jokanaan, Salome can at last give voice to her longings. Herod commands the soldiers to kill her.