Agent Carl is one of the INS agents that comes to investigate a report of illegal immigrants working in the Smith household in "American Dream Factory". When Paco slacks on his work in Stan's teddy bear sweatshop to go on dates with Hayley, and Stan convinces him to break up with her. Hayley is in such a rage that she calls the INS and gives them a tip about the factory Stan is running. INS Agent Hopkins comes to investigate, and while he don't find the immigrants he do find evidence that leads them to watch the house constantly. Realizing that they can't work in the house, Stan and Steve attempt to smuggle them to a warehouse where they can finish the huge teddy bear order Stan has. However, the INS catches them trying to push the van loaded with teddy bears out without starting the engine. Stan tries to first say they have car trouble but Agent Hopkins has Agent Carl demonstrate there is no problem with the engine. Then Stan lies that the Mexicans are part of Steve's band and asks to allow them to perform with Steve at the Langley 4th of July Festival. Agent Hopkins agrees, but says that the agents will be in the audience, and will have to be deported immediately after.
At the festival, Steve and the Mexicans sing John Denver's song "Take Me Home, Country Roads" - the only one they know in English about America they used to sing while dreaming of immigrating. Hearing it, Stan realizes that they love America so much he can't allow them to be deported; Hayley also realizes that she was hypocritical to defend illegal immigration but also use the INS for petty revenge. After the song, the two throw all the Fourth of July bears as free gifts into the audience, which causes such a mob to get them that the INS agents are temporarily unable to act as the Mexicans are smuggled away.