Sometime during the workday, the Burger World Manager has a small talk with Beavis and Butt-head about customers complaining about the fries. Pulling out the fryer baskets, they soon come to find out that the boy's experiments and stunts have long collected in the fryer (including various bugs and trash, and used bandages). The manager sternly orders them to change the oil before even leaving their shift.
As Butt-head mentions This sucks!, the two leave their positions and soon arrive for oil, but of a mechanical nature at an auto repair shop. Stating they are there to "change the oil", a small conversation with the managing mechanic allows the boys to open up a tab and nab themselves candy bars and naked lady air fresheners along with the long needed "oil" for the change.
Heading back, Beavis finds a dead rat caught and found while fiddling with the fryers. Obviously not knowing what to do, the two grab drink cups and draw the hot oil by hand. At the halfway point, they come to stop and dump the motor oil into the fryer before Butt-head throws in an entire bag of fish fillets to "test fry". Taking the cups of oil to the back and dumping them into the street drain, some noise and toxic smoke breaks out and the two get a feeling to go home.
Arriving at home, the two watch the news of how the oil in the fryer obviously destroyed their workplace and remains closed until by word of the fire inspector. The following story soon sees environmentalists working to save wildlife off of the coast of Greece- Where Beavis and Butthead mistakenly take them as coming to cook the fish with the "oil" they are covered in.