The Sinclair family is celebrating the upcoming arrival of the Bunch Beetles, a species of insect who come to Pangaea annually to eat all the cider poppies which tend to grow excessively around spring. However, after the countdown, the Beetles don't return, much to the confusion of everyone. Four days later, without the Bunch Beetles, the cider poppies have completely grown out of control and are overtaking Pangaea.
As the Sinclairs and Earl's best friend, Roy, try to deal with the situation by trimming down the cider poppies, one of the Bunch Beetles named Stan unexpectedly arrives at the Sinclair's house. He explains that he became lost on his way to the mating ground (in a swamp), but he needs to get there now since Bunch Beetles have a short lifespan. Charlene volunteers to help Stan but when they get to the swamp they discover that FruitCo, a subsidiary of the WESAYSO corporation has built a wax fruit factory over the mating ground's swamp. They also learn from one of the factory workers that all Bunch Beetles who arrived at the factory have been sprayed with insecticide, causing the entire species to become extinct thus making Stan the last of his kind.
Charlene reports the extinction of the Bunch Beetles on DNN (Dinosaur News Network) and even points out how the WESAYSO corporation is also responsible for the cider poppy crisis. But Earl takes over the interview and tries to defend the company's actions by claiming that it was all in the name of progress. B.P. Richfield watches the interview from his trailer after getting a call from his boss, knowing that it spells trouble for WESAYSO's public relations. Intrigued by Earl’s comments, he decides to have Earl be in charge of a task force to fix the problem.
When Earl and Roy are being interviewed about the task force, they explain that they're going to spray the cider poppies with defoliant and assures reporters that it is safe, even though it was donated to them by B.P. Richfield who prefers to remain anonymous. Robbie questions Earl about spraying the continent with poison and asks if there is a safer alternative. Charlene suggests that they trim back the vines and try to live with them for a while until nature restores the balance, but Earl refuses, claiming it will take too long. The defoliant is sprayed, which gets rid of the cider poppies, but the next day it is revealed that not only are all the cider poppies gone; but all plant life on Pangea has been killed too, resulting in a famine. Earl then reassures his family that Mr. Richfield has found a way to bring back the plants.
In Richfield's office, he, Earl, and Roy try to figure out how to revive the plants. Richfield states that they have to make it rain and in order to do so, they need clouds, which he thinks come from volcanoes (which actually produce smoke). Richfield states that in order to make clouds they need to set off a bunch of volcanoes by dropping bombs in them. Earl is reluctant since their last idea failed, but is convinced by Richfield not to lose faith in progress and they all go with the plan.
Soon, bombs are dropped into volcanoes all around the world, which create giant thick black clouds that cover the entire planet. Earl thinks the clouds will create rain, but the rest of the Sinclair family doubt that will happen. On the news, news anchor Howard Handupme reports that the clouds are blocking off the sun and causing global temperatures to drop precipitously. Earl tries to stay positive, claiming that the sun will come out and melt the snow, making the plants grow. But Handupme reports that due to the thickness of the clouds, scientists have predicted that it will be tens of thousands of years before the sun shines over Pangaea again, thus beginning the Ice Age. Earl calls Mr. Richfield about the problem, but Richfield refuses to listen, claiming it is a good thing because everyone is panic buying WESAYSO's products like logs, heaters, blankets and hot cocoa mixes. When Earl vainly tries to point out the upcoming Apocalypse, Mr. Richfield, exultant, declares his only problem is to try and decide on what to do with all of the money he's made.
Later, Earl apologizes to Stan for destroying his mating grounds and the extinction of the Bunch Beetles. He then apologizes to his family for his unintentional part in his WESAYSO'S bringing about the end of the world, his overdependant faith in progress and technology and his disrespect for nature. Baby asks if the family will have to move but Earl replies that there's no other place for them to move to. Baby then asks what'll happen to them but Earl sadly looks at his family and says he doesn't know. Robbie and Charlene assure Baby that whatever happens, they'll all stay together as a family. Earl also reassures them that they will survive, stating that dinosaurs have been on Earth for 150 million years and reaffirming his faith that their species won't go extinct. An ominous silence falls as the Sinclairs look out of the window in uncertainty as the snow continues to slowly bury their home, the scene cutting to the wax fruit factory that started the disaster as it too is consumed by the volcanic winter.
After taking a look at the long-range forecast, Howard signs off for the last time by saying a final farewell to the viewers, ending the series on an extremely somber note.