Humans from the year 3045 are traveling to South Park through a recently discovered time portal and are looking for work. When the boys try to earn some extra money, the time-traveling immigrants are willing to do the same work for next to nothing, causing the boys to lose their jobs.
Early in the morning, a mysterious, almost alien man appears, entering from some kind of portal. Unfamiliar with his surroundings, he is hit by a car.
A while later, the boys offer to shovel the snow off of a woman's driveway and Cartman proposes a ridiculously high price for it ($8,000). When she offers a more realistic price ($10), Cartman negotiates by telling her "Ma'am, you're breaking my balls" to get it a bit higher ($15). The other boys work hard while Cartman lounges around on the woman's doorstep, chatting to someone on his mobile phone. Kyle objects to Cartman's laziness and, after an argument, hits him with his shovel. The woman invites the boys in to allow Cartman's bleeding to heal. Inside, they see a report on CNN about a man who's come from a thousand years in the future. Further in the newscast, it is reported that the time-traveler is looking for work because of the overpopulation in his time, and that the money he earns will be enough to feed his family in 3045. The time portal he took is said to follow "Terminator rules," as it is a one-way portal (as opposed to the two-way "Back to the Future rules", or "Timerider rules", the latter which are "just plain silly").
Stan returns home to see that his parents have been watching the newscast. Apparently, the first immigrant's success has inspired another one to come. Stan goes to bed with a cool sentiment about the two men. Early the next morning, several other immigrants are coming in, and some bring their wives and children.
When the boys offer snow-shoveling again, they find that time immigrants have been hired to do most of the shoveling jobs for very low pay (the one who took the boys' job offered 25¢).
We see CNN again to explain the future Americans. They are a "hairless, uniform mix of all races" with the same skin color, and their language is also mixed from "all world languages," sounding guttural.
Working men are arguing at a meeting with various unions in attendance, discussing their intolerance of the immigrants. The foreman of this meeting, construction worker Darryl Weathers, addresses that "we worked long and hard" to get their pay high enough to "make a decent living." He then angrily states that the immigrants are looking to do that work for low wages. "DEY TOOK OUR JEBS!!" The other men agree and yell out, "dey took our jebs!" The men repeat (and mangle) this line throughout the episode. The chants decline to sound like the now infamous "Dey tuk er jerbs!" chant. It eventually becomes completely unintelligible, including the example "Derka Dur!"
As the immigrants from the future continue to come in more and more, Stan reports to his parents that he was attending that rally to protest them. The Marshes have hired one such immigrant as a housekeeper for 10¢ an hour. Stan calls the people from the future "goobacks," a pejorative term referring to the goo on their bodies, which is a side effect of time-traveling. Stan's parents are shocked with what he's saying. Randy says, "They're only taking the small menial jobs that nobody else really wants to do." He lectures that it's wrong to judge the immigrants, because they came from crappy conditions compared to the present day.
On The O'Reilly Factor, Weathers speaks as "pissed-off white-trash redneck conservative" opposite "aging hippie liberal douche." After some "They took our jobs!", the liberal says, "Your ancestors came to America as immigrants. What right do you have to turn these people away?". All the bewildered redneck can say is, once again, "Dey Turk errr jerrrbs!", along with some help from fellow rednecks in the audience.
Life in South Park is accommodating itself to the immigrants to a point where Mr. Garrison must teach in both current English and the future language. The kids object to it, but the hippie speaks in the immigrants' defense. The goobacks continue to adopt the stereotype of the disaffected immigrant, right down to the gooback teens, cruising around in a futuristic lowrider.
Weathers holds another meeting, reading that the local congressman has judged that "your solution of shooting everyone who crosses the time border is inhumane." Weathers decides the group has to "stop the future from happening," which the group supports.
The boys go to a fast-food restaurant where the staff is made up of the immigrants. The cashier doesn't understand Stan's order, asking "Chick-en sand-which?", and the manager (who is the best speaker of English in the restaurant) doesn't either. Just as Randy enters, Stan becomes upset and yells, "I want a goddamn cheeseburger and some god damn fries, you fucking Goobacks!" Stan's parents just so happen to walk in when Stan begins to yell, and when they hear him, they become very angry at him for being "timecist".
Back at the rally, someone suggests that the protesters get into a pile and "get gay." Weathers likes the idea, and is met with initial resistance, but convinces the unemployed men that this is the only way to stop the men and women from the future from coming. The protesters start to take off their clothes and get in a pile in front of an immigrant section of town (called Little Future).
Randy arrives at work and has brought in Stan to sit in his office bored, because of his grounding for his "intolerant mouth." He finds that a future immigrant who knows geology and will work for less money has taken his job. He then descends to the same anger as the other men whose jobs were taken.
CNN covers the protest at the time border, in which many men have gotten into the pile. Randy speaks for the rest of the unemployed men on their position. The hippie speaks against it. As the microphone is turned in Stan's direction, Stan, disturbed with this protest, sees that it's wrong to call the immigrants "goobacks" because "they're no different from us." Stan then says that he understands that the time people live in poverty and they're just trying to live, but realizes that poor societies often hurt other societies, instead of helping it. He suggests that the people of the present should try to make the future better so the immigrants won't need to come. The men in the pile realize that Stan's right.
The present-day people start to plant trees, recycle, give to the poor, use less polluting energy, and in general clean up, all to an environmental song. The immigrants fade, and the work continues. Stan suddenly stops and realizes that "this is gay." Kyle agrees that "this is really gay." Cartman states that it's gayer than when the men were in the pile having sex. Stan apologizes and says, "Everyone back in the pile." The men rush back to the pile with the last straggler yelling the now completely unintelligible "Derka der!".