Distinguished Professor Gordon explains that Earth is being tormented by periodic "sex rays", which send people into a sexual frenzy. When one of the rays hits the passenger aircraft carrying Flesh Gordon and Dale Ardor, the pilots abandon the controls and everyone aboard has manic sex. Realizing no one is flying the plane, Flesh temporarily snaps out of the effects of the ray and tries to pilot the vehicle, to no avail. Seeing no other solution, he takes a parachute and escapes with Dale from the imminent crash. They land near the workshop of Dr. Flexi Jerkoff, who has a plan to stop the sex rays at their source.
They travel to the planet Porno aboard Jerkoff's phallic rocket ship, and are briefly hit by a sex ray, resulting in a frantic three-way orgy. After being shot down by the minions of Emperor Wang, the heroes crash land. They run away from their pursuers and enter a nearby cave, where several one-eyed Penisauruses attack them. Wang's soldiers then shoot down the creatures and imprison the earthlings. They are brought before Wang, who is presiding over a sex orgy of more than a dozen men and women. Jerkoff is sent to work in the palace's laboratory, while Wang announces his intention to marry Dale. Flesh is sentenced to death, but is saved from execution by Queen Amora, who takes him as her sex slave. To achieve this, Amora takes Flesh to her ship, which departs for the stars while she hypnotizes him and they make love.
Angry at her rebellious attitude, Wang shoots down Amora's airship, and Flesh is the only survivor. Jerkoff escapes the palace and reunites with Flesh, and they resume their efforts to defeat Emperor Wang. To aid them in their quest, Amora's spirit lends them her "power pasties", which turn out to be powerful weapons against Porno's soldiers. The heroes manage to interrupt Wang and Dale's wedding before it is fully realized, and a fight ensues. During it, Dale is kidnapped by Amazonian lesbians. Their leader, Chief Nellie, attempts to initiate Dale into their warrior sex cult. Flesh and Jerkoff save her, unexpectedly aided by Prince Precious of the Forest Kingdom.
With help from their new ally, Jerkoff builds a weapon to destroy the sex ray. During the mission, they confront Wang and trick his "rapist robots" into turning on him. However, Wang escapes, seeking the aid of the towering idol of the Great God Porno. Porno comes to life and captures Dale, blandly commenting all the time as they flee. Shooting the living idol, Jerkoff frees Dale and causes the god to fall on Wang. The crash destroys the sex ray and kills them both. Flesh, Dale, and Jerkoff are celebrated as heroes of the planet Porno and then return to the Earth.
Jason Williams as Flesh Gordon
Suzanne Fields as Dale Ardor
Joseph Hudgins as Dr. Flexi Jerkoff
William Dennis Hunt as Emperor Wang the Perverted
John Hoyt as Professor Gordon
Candy Samples as Chief Nellie
Mycle Brandy as Prince Precious
Nora Wieternik as Amora, Queen of Magic
Lance Larsen as Guard for Emperor Wang
Robert V. Greene (voice) as Narrator
Craig T. Nelson (uncredited voice) as The Great God Porno