As tensions escalate within the U.S. government concerning the precarious situation of the nation’s avocado supply, the formidable "Piranha" tribe—comprised of cannibal women residing in the enigmatic "Avocado Jungle"—begins to unleash chaos. This tribe is infamous for their ritualistic slaughter of men, drawing the attention of Professor Margo Hunt, portrayed by Shannon Tweed, who is a distinguished feminist studies expert at Spritzer College. The government recruits her to establish a connection with these fearsome women. Accompanied by Jim (Bill Maher), a chauvinistic guide, and Bunny (Karen M. Waldron), a sweetly naive undergraduate, Dr. Hunt sets off on a dangerous expedition into the core of the Avocado Jungle.
As the trio delves deeper, they encounter the "Donnahew" tribe, a subservient group of men living under the Piranha women's shadow. Their journey is fraught with peril, leading them to confront the very women they sought to reach. The Piranha women, now commanded by Dr. Kurtz (Adrienne Barbeau), a former colleague turned foe, are determined to protect their territory.
Dr. Hunt’s arrival ignites intense discussions about the ethics of male sacrifice and the exploitation faced by the Piranha tribe. Meanwhile, Bunny finds herself captivated by the tribe’s customs and ultimately decides to become one of them, with Jim being her first intended "sacrifice." Yet, she falters when it comes to the act, prompting Dr. Hunt to escape the Piranha women’s grip with the assistance of Jean-Pierre (Brett Stimely), a charming and resourceful ally also marked for sacrifice.
Navigating the perilous terrain, Dr. Hunt uncovers another group of cannibal women, the Barracuda Women, who are embroiled in a bitter conflict with the Piranha tribe over the right condiment for their sacrificial feasts. Armed with this crucial insight, Dr. Hunt bravely returns to the Piranha stronghold to rescue Bunny, Jim, and Jean-Pierre.
The climax intensifies as Dr. Hunt and Dr. Kurtz engage in a fierce confrontation to establish dominance. Their battle culminates in a dramatic moment where Dr. Hunt pierces Kurtz with a fencing sword. In her dying breath, Kurtz unveils her true intentions: having ruled the Piranha tribe, she is now irreversibly trapped in this primal existence, unable to return to the comforts of civilization or the talk-show limelight. With an air of tragic irony, she meets her end by leaping into a pit filled with lethal piranhas.
As Dr. Hunt uncovers the government's sinister strategy to domesticate the Piranha women through aerobics and a taste of cosmopolitan life, she resolutely chooses not to sell out her principles. Instead, she establishes an unprecedented alliance between the feuding cannibal tribes, conducting a series of enlightening group discussions that bridge the gap between former adversaries and ultimately foster a surprising peace.
Meanwhile, the romantic plots surrounding Dr. Hunt's colleagues reach a joyful crescendo. Bunny and Jim are preparing for their wedding in a celebration of their love, while Jean-Pierre, inspired by the professor’s unwavering commitment to feminist studies, courageously decides to enroll at her university. This marks the beginning of his transformation into a thoughtful companion for Dr. Hunt. As the film concludes, it becomes evident that this unlikely trio has grown stronger together, their bonds forged in the fires of adventure and challenge.
