A mysterious Shepherd is brought before King Roger. The Church officials want him punished for his heretical preaching, but Roger's queen Roxana pleads with the king to let the Shepherd speak first.
The Shepherd seduces the court with descriptions of his hedonistic faith. They follow him in a wild Bacchic dance, Roxana among them. As the long night ends, Roger seeks out the Shepherd and his followers. He is agonized by the temptation to follow them, but resists. Alone, he hails the new dawn.