Zoroastre, founder of the Magi, is exiled from Bactria, where the sorcerer Abramane yearns for power, to be achieved with the Bactrian princess Erinice. Zoroastre, banished, is parted from his beloved Amélite, heiress to the throne of Bactria. Through the help of Oromases, King of the Genii, Zoroastre seeks to rescue Amélite, captured and tormented by Erinice. He is successful, but Abramane engineers, through his magic, further difficulties, championing the powers of darkness against the powers of light. Eventual victory allows Amélite to be crowned queen, with her consort Zoroastre.
Zoroastre was revised in 1756 and revived in Paris in 1770. Its plot is original in its study of conflict between darkness and light, evil and good, an idea that seems to suggest other contemporary preoccupations of the Enlightenment. The opera itself relies heavily on spectacular and repeated divine intervention for its eventual happy outcome.