The old King of Spain, having conquered Fez and killed the Moorish monarch, has taken the orphaned prince Abdelazer under his protection and in time made him General. Abdelazer, though always courageous, has the desire of revenge ever uppermost, and to gain influence, rather than from any love, he becomes the Queen’s paramour. She, being a lustful and wicked woman, joins with the Moor in poisoning her husband, at whose death Philip, her second son, newly returned victor from a martial expedition, leaving his army at some distance, rushes in mad with rage and publicly accuses his mother of adultery with Abdelazer. She is greatly incensed, but Cardinal Mendozo, as Protector of the King, promptly banishes her gallant. The young King Ferdinand, however, to please Florella, the Moor’s wife, whom he loves, revokes this decree. Abdelazer, in revenge, next orders his native officer Osmin to kill Philip and the Cardinal. They escape by night disguised as monks, whilst Abdelazer alarms the castle with cries of treason and tells the King that Philip and the Cardinal are plotting to murder him. Ferdinand orders Abdelazer to follow them, intending to visit Florella during her husband’s absence. Abdelazer, fully aware of his plan, out of pride and mischief furnishes Florella with a dagger, bidding her stab the King if he persists in his suit. Elvira, the Queen Mother’s confidante, Watches the King enter Florella’s apartment and conveys the news to her Mistress who, with dissembled reluctance, informs Alonzo, the Moor’s brother-in-law. Florella resists the King’s solicitations and produces the dagger threatening to stab herself. At this juncture the Queen rushes in and, feigning to think that Florella was about to attempt the King’s life, kills her. Her motive for this deed is, in reality, jealousy.