In the year 40.000, Barbarella, the best astro-pilot of earth, is given by the President of the Republic of Earth a mission of the highest importance. She has to find Duran-Duran, a scientific exile on the planet Lytheon, inventor of the Polyray 4, a terrible weapon threatening the peace in the galaxy.
After a crash landing on the little planet, Barbarella is captured by a malevolent child group who deliver her to robots-dolls. Delivered by Mark Hand, a bounty hunter who knows how to made rewarded, she decides to go to the city of Sogo where the researched scientist could have hide. But her spaceship fails again and crashes in the labyrinth of Sogo, bottom of the city and of the city of dreams in which lives the Great Tyrant. There, Barbarella meets Pygar, the blind bird man, and the professor Ping who confirms the presence of Duran-Duran in the city of dreams. Although it is theoretically impossible to leave the labyrinth, Barbarella escapes it, taken in Pygar's arms who finds back his ability to fly.
After a rough fight against the guardians of the Tyrant when they approach the city, Barbarella and Pygar succeed in entering it. They are quickly captured by the Great Tyrant, who proves to be a very beautiful woman, and her servant the « Concierge». After a failed escape attempt, Barbarella is sent in a glass cell in pasture to a horde of parrots, while Pygar is delivered to Matmos, the living liquid energy that governs the planet.
Barbarella is saved in extremis by Dildano, the revolutionary force chief who plans to reverse the Great Tyrant and to restore hope to men and women imprisoned in the labyrinth. The former confirms the presence of the scientist in the palace. Against the invisible and secret key of the bedroom of the Great Tyrant, Barbarella offers her weapons and her spaceship to the
rebels to help them to reverse the despot. But she is once again arrested by the Concierge who submits her to the killing pleasure machine...
Spoiler ! the end of the story is revealed below…
Her preasure thirst is so great that Barbarella does not succumb to it and even destroys the terrible machine. There, she understands that the Concierge and Duran-Duran are only one. Wanting to take the power over the planet and over the Earth, he pushes Barbarella to the bedroom of fantasies, the bedroom of the Great Tyrant where nobody can enter under sorrow to see himslef buried by the Matmos.
Barbarella and the Great Tyrant are both prisoners of the bedroom of fantasies. But while the social-climber earthling self-proclaims Great Tyrant, the people of the labyrinth revolts. The scientist preserve the advantage by using his terrible invention, Polyray 4 that tames the rebellion. Meanwhile, the Matmos begins to invade and to gobble the city of dreams. Protected by a bubble, the two women are saved by Pygar while Duran-Duran perishes within the city of Sogo.