The crew is returning from a delivery to "the planet of the Moochers" who cleaned out their entire food supply. Still two days from Earth they spot an uncharted planet hoping to find a place to eat. Although no civilization is evident they discover hundreds of ditches filled with what look to be small morsels of fried shrimp. Leela eats one but is unable to stop there. Fry and Bender also begin eating them and likewise find them delicious and addictive. The three of them decide that these morsels are so good they should bring some with them on their return to Earth. After filling the ship with them they arrive back at Earth where everyone at Planet Express eats some and also finding them irresistible. Having never seen these things before they decide to give it a name. Hermes performs a search of government records and finds that there are only two unused product names, one of them being popplers which is the name they adopt for this new food.
Bender gives them the idea to sell popplers for profit as street corner vendors. While doing so they are approached by Joseph Gilman, the CEO of the fast food company Fishy Joe's, who offers to sell the popplers on their behalf in all of his restaurants throughout the galaxy and split the profits. Soon the entire galaxy is addicted to them, prompting hippy activist Free Waterfall, Jr. to organize Earth protests against the practice of eating popplers.
Meanwhile, Fry continues to leave old empty buckets of popplers laying around the office, so Leela prepares to discard them. Just as she is about to eat one of the old but still edible popplers it uncurls, opens its eyes and calls her "mama!" This prompts Leela, and soon the rest of the Planet Express crew, to join the anti-poppler protests to prevent others from eating popplers which they now realize are intelligent living creatures.
Shortly after this, the Omicronians invade earth where they reveal a startling fact: the uncharted planet that Leela and Fry had landed on is a nursery planet in the Omicronian sector of the galaxy, and the popplers are actually incubating Omicronian babies. Lrrr and Ndnd are furious and insist upon their right to eat one human for every poppler consumed. However Kif and Zapp Brannigan who are conducting negotiations with the Omicronians reveal that over 198 billion popplers have been eaten and inform them that there are not this many humans. At the conclusion of the negotiations Zapp is able to convince the Omicronians to instead eat only one human. They decide to eat the first human who consumed a poppler - Leela!
That night, a live event featuring Leela being eaten by Lrrr is shown on TV. But Zapp has a plan - he swaps an orangutan for Leela. Kif gives the ape a Leela-style haircut and covers one of its eyes with a patch the same color as its fur. The orangutan is wheeled out to Lrrr and Ndnd, who are unable to recognize one human from another. Just as Lrrr opens his mouth and prepares to eat the orangutan Free Waterfall, Jr. runs up to them and tells them that they've been tricked, that it's not Leela but an orangutan "one of Mother Earth's most precious creatures." When they realize they've been tricked they insist Zapp bring them the real Leela.
Leela is brought out. As Lrrr places Leela into his mouth the little poppler who earlier called Leela "mama!" runs up, jumping into Leela's mouth. The little poppler, who now clearly resembles an Omicronian, speaks into the microphone saying that her name is Jrrr and Leela is her friend. Jrrr says to Lrrr that if he eats Leela, he eats Jrrr as well. Touched by this display of friendship and not wanting to eat one of his young, Lrrr decides to release Leela - but eats Free Waterfall, Jr. instead. The Omicronians decide to leave Earth in peace just as Lrrr begins to experience the side-effects of a drug-like high from eating the "smelly hippy" and begins to hallucinate as they depart Earth.