In 48 B.C. Caesar pursues Pompey from Pharsalia to Egypt. Ptolemy, now sovereign after deposing his older sister, Cleopatra, attempts to curry favor with Caesar by presenting the conquerer with the head of Pompey, borne by his satraps, Pothinos and Achillas. To win Caesar's support from her brother, Cleopatra hides herself in a rug, which Apollodorus, her minion, presents to Caesar. The Roman is immediately infatuated; banishing Ptolemy, he declares Cleopatra Egypt's sole sovereign and takes her as his concubine. A son, Caesarion, is born of their union.
Caesar, however, must return to Italy. Although he is briefly reunited with Cleopatra during a magnificent reception for the queen in Rome, Caesar is assassinated shortly thereafter, and his paramour returns to Egypt.
When Mark Antony, Caesar's protégé, beholds Cleopatra aboard her barque at Tarsus some years later, he is smitten and becomes both her lover and military ally. Their liaison notwithstanding, Antony, to consolidate his position in Rome, marries Octavia, sister of the ambitious Octavian. The marriage satisfies no one. Cleopatra is infuriated, and Antony, tiring of his Roman wife, returns to Egypt. There he flaunts his liaison by marrying Cleopatra in a public ceremony.
Sensing Antony's weakness, Octavian attacks and defeats his forces at Actium. Alarmed, Cleopatra withdraws her fleet and seeks refuge in her tomb. Falsely informed that she is dead, Antony stabs himself. Borne to her sanctuary, he expires in her arms. In despair, Cleopatra applies an asp to her breast and dies of its poison.