A brilliant scientist discovers an asteroid on a collision course with Earth but is soon perplexed by the appearance of a UFO accompanying it. As he ventures outside to investigate, the UFO mysteriously disappears. Flashing back to the past, we see how Daffy Duck, voiced by Eric Bauza, and Porky Pig, portrayed by Fred Tatasciore, were raised by a farmer named Jim. Jim leaves them a promise, to stay together and care for one another, which becomes a hallmark of their relationship.
In the present day, Daffy and Porky are getting ready for a house inspection, confident they will pass. This confidence is soon shattered when a giant hole in their roof, oozing green slime, catches them off guard. Their inspector, Laraine Newman as Mrs. Grecht, sternly gives them ten days to fix the roof or face condemnation of their beloved home. Following a series of job failures due to Daffy's comical misbehavior, the duo crosses paths with Petunia Pig, voiced by Candi Milo, a scientist who works at the Goodie Gum factory in search of the perfect gum flavor. She offers them a lifeline in the form of a job, which they readily accept.
Everything seems to be going smoothly as they finish their first shift without any mishaps. However, paranoia sets in for Daffy when he notices the scientist sneakily carrying a briefcase filled with the same goo from their roof. Ignoring Daffy's worries, Porky brushes it off as unfounded paranoia. As fate would have it, the newly introduced gum flavor is launched globally, and chaos ensues when Daffy realizes that everyone consuming the gum is transformed into a zombie. At the launch party, when he tries to sound the alarm, he inadvertently makes a fool of himself, leading to his arrest and losing their jobs in the process.
As the situation escalates, Petunia learns that an alien invader is behind the contamination of the gum. The Invader, voiced by Peter MacNicol, commands the gum and turns it into a terrifying monster intended to eliminate anyone who stands in his way, but they're able to burn it down. This prompts a brainstorm session among Daffy, Porky, and Petunia, who devise a plan to spray people with Petunia's rotten egg extract to make them spit out the threatening gum before it ignites. Concerned about Daffy’s tendency for chaos, Porky insists he stay back to produce more of the extract.
Despite Porky and Petunia's successes, Daffy's impulsive desire to join the fray leads to chaos and destruction of their resources. As the Invader escalates the situation by inflating the evilness of the gum, the entire town becomes an army hunting them down. Eventually, Porky and Daffy are captured by the Invader, manipulated into a battle that lands them in a laser-protected cage. With the population under his control, the Invader activates his sinister plan, instructing everyone to blow up gum bubbles large enough to encapsulate the whole planet.
In a twist of fate, Daffy and Porky find common ground, escaping their confines when their heartfelt tears short circuit the cage. They successfully free Petunia and the scientist just in time to pop the looming gum bubble. However, they discover that the Invader's intentions were not entirely malicious; he wanted to use the gum to bounce the asteroid away, motivated by his fondness for boba instead of destruction. As they recall Petunia's explosive gum, the team, aided by the Invader and the scientist, infiltrates the asteroid's weak link, planting a stash of gum near a giant crystal to be chewed up by novelty teeth.
When the plan misfires, and the teeth topple over, Porky ingeniously directs Daffy to embrace his wild antics, prompting stalactite crystals to tumble down and essentially "chew" the gum. Yet, when the evacuation attempt is made, Daffy finds himself trapped, and Porky refuses to abandon him. As the asteroid nears its end, Petunia can only watch in angst as it bursts before colliding with Earth.
In a surprising twist, Daffy and Porky survive, hanging on to debris that plummets back to Earth. The crystal they cling to brings with it a new gum flavor, which, though wild, captures the hearts of the town. As the duo survey the remains of their house, Porky discovers a hidden $5 million home insurance contract left by Jim that allows them to rebuild their home.
In a humorous mid-credits scene, Mrs. Grecht pays their property a visit for a follow-up inspection only to be met with the flashy upgrades of Porky, Daffy, and Petunia, sending her into a fit of frustration.
