Orsames, heir to the Dacian throne, has been kept in a castle from His infancy, never having seen any human being save his old tutor, Geron, owing to an Oracle which foretold great cruelties and mischiefs If he should be allowed to wear the crown. The Queen of Dacia designs Her daughter Cleomena as her successor, and with this intent gives her An Amazonian education. The Dacians and Scythians are at war, but Thersander, The Scythian prince, has joined the Dacians under the name Of Clemanthis, inasmuch as he loves the princess, who in her turn Becomes enamoured of him. He is recognized but not betrayed by Urania, a Scythian lady who, her lover Amintas having been previously captured, allows herself to be taken prisoner and presented to Cleomena. Amintas is confined in the old castle where Urania, visiting him, is accidently seen by Orsames. He is, however, persuaded by Geron that it is an apparition. Amintas is freed by Urania, who has gained Cleomena’s friendship. Honorius, the Dacian general, offers Thersander his daughter Olympia, and the young Scythian is obliged to feign acceptance. Cleomena hears Honorius telling the Queen his design and goes off enraged, only to see Thersander seemingly courting Olympia. She raves and threatens to kill him, but eventually parts with disdain, bidding him quit the place. Orsames is now brought from the castle during his sleep, crowned, seated on the throne and treated in every respect as King. His power is acknowledged, the Queen kneels before him, and Olympia entering, he falls violently in love with her. At a supposed contradiction he orders one courtier to instant execution and another to be cast into the sea. Immediately after, during a banquet, a narcotic is mingled with his wine and he is conveyed back to the castle whilst under its influence, leaving the Queen fearful that her experiment is of no avail as he has displayed so tyrannical and cruel a nature.