It's May 14, and the Sinclair family is awaiting the arrival of the the bunch beetles to fly down and eat the cider poppy vine that is growing everywhere in the world, while Earl is more interested in cooking on his new grill. When the moment comes close, Fran thinks the beetles are coming at a good time considering how thick the cider poppy is this year. But after a televised countdown finishes and the bunch beetles fail to appear, it is not clear why there was a delay; they were never late before.
Four days later, the Dinosaurs are all worried about where the bunch beetles are; the cider poppy is now growing to the point of of being out of control. While Earl, Charlene and Roy trim the poppies that are starting to overrun the house, they end up meeting a horomonally-charged bunch beetle named Stan. He's hoping to start meeting girls and Earl, Charlene and Roy learn the baby beetles are the ones who eat the cider poppy. Stan had gotten himself lost on his way to the swamp, and together, she agrees to show him the way there, with Stan trying to pick on her the whole way.
Upon arriving, Charlene and Stan learn that the swamp was paved over to build a Wax Fruit factory which is run by the WESAYSO corporation. They demand an interview and Charlene and Stan both appear on TV in the Sinclairs' kitchen, blaming WESAYSO for killing the bunch beetles, a vital part of the ecosystem, to make progress for the sake of progress. Earl then barges in and tries to deny the company's responsibility; saying nature is okay to dispose of as long as you get some modern conveniences and technological enhancements out of the deal. At his work station, Mr. Richfield is hearing from the executives at WESAYSO about how the company is under fire on the news. But seeing Earl on TV gives Mr. Richfield an idea: to protect the image of WESAYSO, and destroy the ever-growing cider poppy without the bunch beetles, Mr. Richfield appoints Earl the environmental task force leader, allowing him to bring in poison to destroy the cider poppy.
After seeing Earl's annoucement to take care of the problem on the news, Robbie and Charlene don't think the plan to cover the supercontinent in poison seems very safe and urge him to consider a safer alternative. Earl dismisses their ideas as 'idiotic and time-consuming' as opposed to his 'exciting and high-tech' solution. It is not long before helicopters fly over the house and Pangaea begins to get coated in plant poison.
The next day, Stan and the Sinclair family watch Howard Handupme's news report that the mass poisoning had successfully killed the cider poppy. However, as a result of simply overdoing it, the poison worked too well; all plant life on Pangaea is dead. When Earl comes downstairs to greet the family, he believes they are overexaggerating about what just happened until he looks outside. Seeing Pangaea is now a barren wasteland, the family starts to blame him for destroying the global food chain.
Concerned about the current status of the planet, Earl and Roy go to see Mr. Richfield, who initally hadn't seen this as his problem. Now faced with the threat of starvation, Mr. Richfield phophecizes that if the Dinosaurs can make it rain, the plants will grow back. His plot involves the planet's volcanoes: whenever they erupt, they spew giant black clouds into the air; surely if the volcanoes can create rainclouds, that would cause a major downpour. But how can they set off a whole bunch of volcanoes? Simple; they will start dropping bombs in the magma. Earl doesn't know about this idea; rationalizing their last quick fix solution had backfired and something this drastic might make it may seem like they are declaring war on nature, but Mr. Richfield reminds him now is not a good time to question his faith in technology. With few options left, Earl reluctantly agrees to his boss's plot.
That night, Earl is enthusiastic about the giant clouds coming in, feeling a storm is brewing and the world's problems will be solved in a manner of minutes. But when he is prompted by Fran to watch the weather forecast, Howard Handupme reports the clouds are thick to the point they are blotting out the sun and surrounding the entire planet; the world is quickly becoming very cold. Earl says this may be a mild setback, as the snow will melt in a few days and there will be lots of water. His thoughts are contradicted as Howard Handupme claims scientists predict that it will be thousands of years before Pangaea will be able to see sunlight again.
Earl calls Mr. Richfield again, saying he thinks they might have gone a little too far, but Mr. Richfield doesn't see the global cooling as a problem considering WESAYSO is having the best quarter ever for sales; with the food and heat crisis, Dinosaurs all over Pangaea have been emptying their pockets towards WESAYSO-brand products. Earl thinks there may not be a next quarter, but Mr. Richfield reprimands him for acting like such a hippie. He decrees the environmentalists merely stand in the way of progress and their job is to pave over them; nothing will stand the way of WESAYSO. Earl takes this time to tell his boss straight out that the world might be doomed, but Mr. Richfield reminds oblivious to the point; all he's concerned about is what to do with all the money he is getting.
Now stuck in the house with nowhere to go, Earl now understands the importance of respecting nature and disaster would occur if nature and technology cannot peacefully co-exist. He apologizes to Stan for killing off his bretheren and the family as he feels very ashamed that he lead the world to the event of doomsday. He tells Baby exactly what happened and not there may not be much of a future for him, Robbie and Charlene; Earth is the only home they have and there's nowhere else they can live. In the end, the Sinclair family stay put with each other to make sure nothing happens to them. With their survival at stake, Fran looks sad as Earl states, "After all, Dinosaurs have been around for 150 million years, and it's not like we're all going to just...disappear."
The series' last image is of newscaster Howard Handupme, who signs off saying, "Good night. ...Goodbye."
As the credits roll, we see the outside of the Sinclairs' house, slowly disappearing under a snowdrift while a depressing instrumental plays, leaving us in no question as to the characters' ultimate fates.