Notorious Baltimore criminal and underground figure Divine goes up againt Connie & Raymond Marble, a sleazy married couple who make a passionate attempt to humiliate her and seize her tabloid-given title as "The Filthiest Peron Alive".
       Sleaze queen Divine lives in a caravan with her mad hippie son Cracker and her 250-pound mother Mama Edie, trying to rest quietly on their laurels as 'the filthiest people alive'. But competition is brewing in the form of Connie and Raymond Marble, who sell heroin to schoolchildren and kidnap and impregnate female hitchhiker, selling the babies to lesbian couples. Finally, they challenge Divine directly, and battle commences...

Underground criminal Divine lives under the pseudonym "Babs Johnson" with her mentally ill, egg-loving mother Edie, delinquent son Crackers, and traveling companion Cotton. They all live together in a pink trailer on the outskirts of Phoenix, Maryland, in front of which can be found a pair of eponymous plastic pink flamingos. After learning that Divine has been named "the filthiest person alive" by a tabloid paper, jealous rivals Connie and Raymond Marble set out to destroy her career but come undone in the process.

The Marbles run an "adoption clinic", which is actually a black market baby ring. They kidnap young women, have them impregnated by their homosexual manservant, Channing, and sell the babies to lesbian couples. The proceeds are used to finance a network of dealers selling heroin in inner-city elementary schools. Raymond also gets money by exposing himself (with large kielbasa sausages tied to his penis) to unsuspecting women in a park and stealing their purses when they flee. The Marbles send a spy named Cookie in the guise of what Crackers thinks is a date. In one of the film's most infamous scenes, the two of them have sex while crushing a live chicken between them as Cotton looks on through a window. Cookie then informs the Marbles about Babs' real identity, her whereabouts, and her family, as well as information about her upcoming birthday party.

The Marbles send a box of human feces to Divine as a birthday present with a card addressing her as "Fatso" and proclaiming themselves "The Filthiest People Alive". Worried her title has been seized, Divine proclaims whoever sent the package must die and her two associates agree. Meanwhile, at the Marbles', Channing dresses up as Connie and Raymond, wearing Connie's clothes and imitating their earlier overheard conversations. When the Marbles return home, they catch Channing in the act and respond with outrage, firing him and locking him in a closet until they can return from their tasks and kick him out for good.

The birthday party begins as the Marbles arrive to spy on it. Divine receives an assortment of gifts, including lice shampoo, a pig's head, and an axe. Later on, they all witness a topless dancing woman with a snake and a contortionist who flexes his anal sphincter in rhythm to the song "Surfin' Bird". One of the guests, the Egg Man, who delivers eggs to Edie daily, confesses his love for her and proposes marriage. She accepts his proposal and he carries Edie off in a wheelbarrow for a honeymoon around the egg industry. The Marbles, disgusted by the reveling, call the police, but this proves unsuccessful as Divine and the other party-goers kill the cops. Divine hacks up their bodies with the axe and the party-goers eat them.

After the party ends, Divine and Crackers head to the Marbles' house, whose address they received from the local gossip Patty Hitler, where they lick and rub everything in their house to spread their "filthiness", which excites them to the point of engaging in oral sex. Licking the furniture later causes it to "reject" the less filthy Marbles when they return home: when they try to sit down, the cushions fly up, throwing them to the floor. Divine and Crackers find Channing locked away, but they have no sympathy for him. Once they're in the basement, Divine and Crackers use a large knife to cut the bonds and free the two captive women, then hand over the knife. The women emasculate Channing offscreen.

Meanwhile, Connie and Raymond burn Divine's beloved trailer to the ground. This is the last straw for Divine, and soon after Connie and Raymond find that Channing has bled to death from his castration and the two girls are gone, Divine takes them hostage at gunpoint. She then calls the local tabloid media to witness the Marbles' trial and execution, as she proclaims her belief in "filth politics":