At King Herod’s palace, the young captain Narraboth admires the princess Salome, who sits at the banquet table with her stepfather, Herod, and his court. A page warns Narraboth that terrible things might happen if he continues to stare at the princess. The voice of Jochanaan is heard from the cistern, where he is kept prisoner, proclaiming the coming of the Messiah, and two soldiers comment on the prophet’s kindness and Herod’s fear of him.

Salome enters, disgusted with Herod’s advances toward her and bored by his guests. Jochanaan’s voice is heard again, cursing the sinful life of Salome’s mother, Herodias. Salome asks about the prophet. The soldiers refuse to let her speak with him, but Narraboth, unable to resist her, orders that Jochanaan be brought forth from the cistern. At first terrified by his appearance, Salome quickly becomes fascinated with Jochanaan’s body, asking him to let her touch his hair, his skin, and finally his lips. Jochanaan rejects her forcefully. Narraboth, who can’t bear to see Salome’s desire for another man, stabs himself. Salome doesn’t notice. Beside herself with excitement, she continues to beg for Jochanaan’s kiss. The prophet tells her to save herself by seeking Christ and retreats into the cistern, cursing Salome.

Herod appears from the palace, looking for the princess and commenting on the strange look of the moon. When he slips in Narraboth’s blood, he suddenly panics and has hallucinations. Herodias angrily dismisses his fantasies and asks him to go back inside with her, but Herod’s attentions are now focused on Salome. He offers her food and wine, but she rejects his advances. From the cistern, Jochanaan resumes his tirades against Herodias, who demands that Herod turn the prophet over to the Jews. Herod refuses, maintaining that Jochanaan is a holy man who has seen God. His words spark an argument among the Jews about the true nature of God, and two Nazarenes talk about the miracles of Jesus. As Jochanaan continues to accuse her, Herodias demands that he be silenced.

Herod asks Salome to dance for him. She refuses, but when he promises to give her anything she wants, she makes him swear to keep his word, and agrees. Ignoring her mother’s pleas to stop, Salome dances seductively for her stepfather. Herod’s delight turns to horror when Salome asks for her reward—the head of Jochanaan on a silver platter. Herod instead offers her riches, half of his kingdom, even the holy curtain of the temple, but Salome won’t be dissuaded and insists he fulfill his oath. Herod finally relents, and as the executioner descends into the cistern, Salome anxiously awaits her prize. The prophet’s head is brought to her, and she passionately addresses Jochanaan, finally kissing his lips. Herod, terrified and disgusted, orders his soldiers to kill Salome.