After dinner, Jerry and Elaine discover a strong smell of body odor, assumed to have been left by a valet who was tasked with parking Jerry’s BMW 5 Series. After a relentless drive home, Elaine’s boyfriend Carl (Nick Bakay) is troubled by the odor coming from Elaine, who then assumes trouble for their relationship. George cannot believe it when he spots his ex-girlfriend, Susan, as a lesbian, and he is turned on by her new outlook on life. Elaine loses her current boyfriend because the odor from the car got stuck in her hair, and he could not stand to be near her. Jerry immediately blames the restaurant he went to the other night, and although the maître d’ initially refuses to pay for car cleaning, he eventually agrees after Jerry had put him inside the car, refusing to let him out unless he pays for half of the price ($250).
Susan’s girlfriend Mona is swayed to heterosexuality by Kramer, which Jerry, Elaine and George cannot understand why, being that Susan’s girlfriend has never been with a man. This angers Susan, due to her dislike of Kramer, and George who is still convinced that he drove Susan to lesbianism. Feeling even more attracted to her after finding this out, George attempts to woo Susan, and appears to be making progress. However, despite his best efforts, the two are seen in the diner by George’s ex Allison – and after introducing them to one another, he can only sigh as the two women exchange amorous glances.
After a complete “de-ionizing” of the car, Jerry, anticipating that the smell is gone, smells it again, and he discovers it is not. Meanwhile, Elaine decides to go to a hair salon to “wash” the smell out of her hair, despite having already taken a thorough shower, and (believing that the smell has gone away) tries to start her relationship with Carl again. He, however, smells the car stench again and tells her that she still smells. Elaine, as well as Jerry, does not know what to do. Jerry then tries to sell the car because the odor has taken on a life of its own and permeated everything, but the dealer claims he cannot sell such a car. Kramer’s relationship with Mona ends when she smells the odor on him, even though he was never in the car. This is because he had borrowed Jerry’s jacket, which was the same one he was wearing in the car. When it cannot be sold, Jerry ends up abandoning the car and its keys out on the street just to get rid of it, even going so far as to offer ownership of the car to a vagrant. However, the vagrant ends up disgusted by the smell and even he rejects Jerry’s offer.