Act 1

Opens in a Byzantine church , with the church choir, led by the Archbishop, intoning Gregorian chants. King Roger enters with his wife, Queen Roxane.

An Arab scholar, Edrisi, warns the King that the faithful wish him to condemn the teachings of a mysterious Shepherd, who has appeared in the countryside. Queen Roxane pleads the case of the Shepherd and when the Shepherd turns up at the church, he so impresses King Roger that he is invited to the palace that evening.

Act 2

The actions takes place in the palace. King Roger is attracted by the Shepherd's colourful music and dancing, until he claims to be God's messenger. Even so, he continues to entrance Queen Roxane, but King Roger orders the Shepherd to be put in chains for blaspheming. The fetters restraining him break, however, and the Shepherd leads his followers, Roxane among them, out into the hills. King Roger follows them, but not before he removes his crown, and becomes a pilgrim too.

Act 3

Out in the open, Edrisi accompanied by Roger approach the ruins of a Greek temple. Roxane greets her husband and endeavours to explain the mysteries of the Shepherd's faith - how he exists everywhere and in everything as some kind of 'life force'. Indeed, subsequently transforming himself into Dionysus, the Shepherd presides over a riotious dance of Bacchantes, into which Roxane disappears. After this, Roger watches the dawn of a new day, his awareness enhanced by the mystical experience he has undergone.