On the grand terrace in Herod's palace, Narraboth, a young Syrian newly appointed captain of the guard, watches the princess Salome, who is with her stepfather, Herod, and her mother Herodias in the adjoining banquet hall. He can do nothing but speak of Salome's beauty. This disturbs the court page, who anxiously tells Narraboth not to gaze at the princess so intently.
Jochanaan, the prophet, calls out from the cistern where he is imprisoned, foretelling the coming of the Messiah. Two soldiers on the terrace talk with a Cappadocian about the enigmatic prophet. Narraboth announces that the princess is approaching, and the page again warns him against watching her.
Salome leaves the banquet hall to get away from Herod's lecherous stare. Jochanaan calls out, and Salome is intrigued. She questions the soldiers about the prophet. Narraboth tries to advise her to return to the banquet. Salome, however, is fascinated by the prophet's voice and asks that the soldiers bring him out to her. When the soldiers refuse, Salome bribes Narraboth with promises of her attention. The captain yields and orders the soldiers to open the well where Jochanaan is kept.
The prophet comes out of the cistern; he denounces Herodias's wicked acts. Salome is fascinated by Jochanaan. After she tells him who she is, Jochanaan insults her, but the princess replies that his voice is like music. Salome asks what she should do, and he tells her to seek the Son of Man. Salome then tells Jochanaan how she admires his body. Salome asks to kiss his mouth, but he spurns her. Narraboth, in anguish, tries to stop Salome, but she continues to plead with Jochanaan, and Narraboth kills himself.
Salome, obsessed, continues begging him to let her kiss his mouth. The prophet declares her accursed and goes down into his cistern. Herod, followed by Herodias and their guests, comes out onto the terrace looking for Salome and slips in Narraboth's blood. He sees the body and is unnerved.
Herodias suggests that they return to the palace, but Herod renews his attentions toward Salome. When Jochanaan calls out again, a noisy argument develops among the Jews in the courtyard. Jochanaan cries out about the Redeemer of Man, and two Nazarenes tell the curious Herod about Christ's miracles. Jochanaan foretells Salome's death.
Herod, seeking a diversion, asks Salome to dance for him, offering her anything if she will comply. Herodias advises Salome to refuse, and at first the girl does. But, receiving Herod's oath that he will give her anything, she agrees despite her mother's angry protests. When she has finished dancing, Salome asks Herod for her reward: Jochanaan's head on a platter. This pleases Herodias, but Herod is shocked. He tries to argue Salome out of her request, but she refuses to yield. At last, Herod acquiesces. Salome waits by the cistern until the executioner hands up Jochanaan's head to her.
Salome asks Jochanaan why his eyes are closed, why his tongue is silent. She praises his body and his hair and his mouth, and she declares her passion for him. Finally, kissing his mouth, she asks if the bitterness upon his lips is the taste of love. Herod orders her killed.