In the far future, three humans—Jiro, Harvey, and Mary—discover that an alien race called the Pasateli intends to conquer humankind by the mysterious "Cleopatra plan". Through the use of a time machine, the three transport their minds into the bodies of members of the historical Cleopatra's court to discover and stop the plan. Harvey, however, vows to use the opportunity to secure the title of the greatest lover who ever lived by having sex with Cleopatra. In the middle of the Roman conquest of Egypt, a group of Egyptians secretly plot a rebellion to overthrow Julius Caesar. The group plans to send Cleopatra to first seduce and then murder Caesar. The Romans discover the group and attack them. Cleopatra escapes, along with her handmaidens Libya and Apollodoria. Cleopatra goes to an ancient wizard, who magically grants her an irresistibly seductive body for her mission. It is at this point that the Jiro, Harvey, and Mary arrive: Mary is now Libya, Harvey finds himself in the body of the wizard's pet leopard Rupa, thwarting his plans to seduce Cleopatra and Jiro finds himself in the body of Ionius, a Greek man captured and enslaved by the Romans. Ionius frees himself and the other slaves by using his knowledge of future technology to make modern hand grenades. They accompany Cleopatra to meet Caesar, who is so overcome by her beauty that he makes her queen of Egypt. Caesar recaptures Ionius and, amused by his fighting skills, orders him to fight in the gladiatorial arena. He gives Ionius a gun to ensure his victory. Ionius proves so popular with the Roman public that Caesar's own popularity soars, leading his senators to conspire to murder both him and Ionius and end their influence. Libya and Apollodoria insist that Cleopatra must murder Caesar; Cleopatra, however, has had a change of heart and keeps putting off the assassination in favor of sex. They accompany Caesar back to Rome, just in time for him to be assassinated by his own senators. Caesar's adopted son, Augustus Caesar—soon to be called Octavian—takes command. Cleopatra tries to continue the plan by seducing Octavian, only to find that he is homosexual and impervious to her charms. Caesar's right-hand man, Marcus Antonius or known as Anthony, fall in love and have sex with Cleopatra. Octavian, however, is attracted to Ionius and spares his life. Finally, during the Battle of Actium where Octavian's fleet, defeats the Anthony-Egyptian fleet, Anthony loses the battle and kills himself, Octavian goes to Cleopatra trying to persuade her to surrender and taken into custody by the Romans. Disappointed by the rejection after Anthony's death, Cleopatra commits suicide by using the venomous bite of an asp. The time travelers return to the future and report that the Cleopatra plan is a scheme by the Pasateli to assume the form of beautiful human women to seduce and destroy Earth's most powerful male leaders. The Pasateli have already taken their human forms and are poised to strike when this information arrives, but Earth is able to root them out and save the world in time.
In 1972, Mushi Productions, who made the film, accepted a deal with Xanadu Productions Inc., a small distributor, to release a subtitled version of the film in the United States to try to save themselves from bankruptcy. When it was released in the United States, Xanadu changed the title to Cleopatra: Queen of Sex and released it with a self-applied X-rating on April 24, 1972, playing at the Bijou theatre and presumably other theatres. It was advertised as the first X-rated animated movie in the United States. However, Fritz the Cat came out with its X-rating from the MPAA before it on April 18, 1972. The movie was not received well by audiences over in America, and was not a success at the box office, due to false advertising claiming it to be a "pornographic" movie, which caused people who saw the film wanting refunds. It was not successful in its native Japan either. Critics give it mixed reviews. Howard Thompson of The New York Times said it was basically a movie that involved "mostly a voluptuously drawn Cleopatra and a bevy of cuties that trot around bare breasted", but praised it for the "lavish backgrounds" and imagery. Variety called the movie "partly sophomoric", with "emphasis on vulgar low comedy", but praised it for having "good animation and color." Cleopatra was not submitted to the MPAA, and may not have received an X-rating if it had been. It is currently unknown if an English dub actually exists or not; however people who claim its existence say that the English dub has since been lost, although it has been subtitled into English. In its native country, it has been released on VHS, VHD,Laserdisc, and DVD throughout the following years. Third Window Films released the film bundled with A Thousand and One Nights on Blu-rayfor the first time and on DVD back on June 18, 2018 for Region 2 territories. Discotek had announced plans to release the film on Blu-ray for Region 1 territories back in July 28, 2019, however there has not been a confirmed release date yet.
