Julius Caesar has conquered Egypt and decides to journey to this corner of his empire.  He approaches the Sphinx on foot appearing as a humble statesman and is not recognized as the great Emperor. He addresses it and is overheard by Cleopatra who doesn't know who he is.  He plays up the mistake, so that later she is shocked to find out he is the mighty Caesar.  He is very paternal toward the beautiful Queen and would like a more intimate relationship, but her heart belongs to Marc Antony.

Caesar meets with King Ptolemy, Theodotus (his tutor), and others of his council.  He learns that Lucius (Lovell) has slain Pompey his rival.  Cleopatra is agonizing over the fact that her world has fallen into the hands of the mighty Romans and that she has been ousted from power by Ptolemy who is her younger brother and her husband.

Caesar and his army are under siege as an offensive is mounted by the forces of Ptolemy trying to take the lighthouse at Alexandria.  Pothinus is held as a prisoner, while Theodotus is dismayed by the burning of the great library and released.  Cleopatra is rolled in a Persian rug and smuggled into the lighthouse by Apollonius to be near Caesar.  Cleopatra orders Ftatateeta to kill Pothinus.  She has crossed Caesar and he will not protect her any further.  Ftatateeta is slain by Rufio for her part in the killing. The rebellion is crushed.

Caesar will return triumphant to Rome, but Cleopatra does not want to leave her land.  She strikes a deal with Caesar that if he spares her son, she will accompany him to Rome.  He places a guard on her fearing she may flee. She breaks the promise once he has left and summons her servant to prepare her some fruit to eat for the journey.  She places her hand in a basket full of figs, but it has a snake in it that kills her.  Caesar is furious that she has been left alone and mourns her death.