The mysterious person, who has come from over a thousand years in the future, is looking for work because of the overpopulation and poverty in his time, and he learns that the money that he earns in the 21st century will be enough to feed his family in 3045.
At a meeting to discuss their concern with the Goobacks, construction worker Darryl Weathers complains that they have worked hard to get their pay high enough to make a living, but now are being ousted by the time-immigrants.
One man suggests everyone start stripping and engaging in a gay orgy; Weathers likes the idea, as it is the only way to stop the immigrants from coming because homosexual couples cannot spawn offspring.
The entire town begins to recycle, install solar and wind power devices, plant trees, give to the poor, etc., hoping to cause the Goobacks to disappear.
Although the townspeople's efforts are successful and the Goobacks begin to fade away, the boys observe that the work is "gayer than all the men getting in a big pile and having sex with each other".
"Goobacks", along with the thirteen other episodes from South Park's eighth season, was released on a three-disc DVD set in the United States on August 29, 2006.