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 (Channing Wilroy), and sell their 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 to unsuspecting women in a park and stealing their purses when they flee. The Marbles send a spy named Cookie (Cookie Mueller) to the trailer in the guise of what Crackers thinks is a date. In one of the film's most infamous scenes, he has sex with her while crushing a live chicken between them as Cotton looks on voyeuristically. Cookie then informs the Marbles about Divine's real identity, her whereabouts, and her family, as well as information about her upcoming birthday party.
The Marbles send human feces to Divine as a birthday "gift" 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 imitating them and react with outrage, firing him and locking him in a closet until they can return from their chores and kick him out for good. The birthday party begins as the Marbles arrive to spy on it. They witness a topless dancing woman with a snake, a contortionist who "lip syncs" a song with his exposed anus, and the gifts Divine receives, such as a pig's head, poppers, and an axe. One of the guests, the Egg Man (Paul Swift), 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 partygoers kill the cops. Divine hacks up their bodies with the axe and the revelers eat them.
After the party ends, Divine and Crackers head to the Marbles' house (they received the address from an offscreen helper, 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 also causes it to "reject" the 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 in a closet where he protests about his treatment by the Marbles, but they are not sympathetic as they tie him up and take him to the basement where the two pregnant girls are held. They free both girls and hand them a knife so they can emasculate him.
Meanwhile, Connie and Raymond burn Divine's beloved trailer to the ground. Afterwards, Crackers, Cotton, and Divine find the trailer reduced to flame and ash. This is the last straw for Divine, and soon after Connie and Raymond find that Channing has bled to death and the two girls are gone, Divine takes them hostage at gunpoint. She then calls the local media to witness the Marbles' trial and execution, as she proclaims her belief in "filth politics":
| “ | Blood does more than turn me on, Mr. Vader. It makes me come. And more than the sight of it, I love the taste of it. The taste of hot, freshly killed blood...Kill everyone now! Condone first degree murder! Advocate cannibalism! Eat shit! Filth are my politics! Filth is my life! Take whatever you like. | ” |
The infamous ending opens as Crackers, Cotton, and Divine walk down the street, where they spot a dog and its owner. The dog defecates on the sidewalk, and Divine sits down next to it. She takes the feces in her hand and puts it in her mouth, proving as the narrator states, she is "not only the filthiest person in the world, but is also the world's filthiest actress".
