Jerry accidentally knocks his girlfriend Jenna’s toothbrush into the toilet, and she uses it before he can tell her. George shows off the new key ring that George Steinbrenner has given everyone in the Yankee organization, celebrating Phil Rizzuto’s induction into the Baseball Hall of Fame. Kramer complains about the failing highway infrastructure after running over an abandoned sewing machine, so he adopts a one-mile piece of the Arthur Burkhardt Expressway through the Adopt a Highway program. Elaine tries to order a new Chinese dish, Supreme Flounder, but she lives across the street from the boundary of the Chinese restaurant’s delivery area. George loses his new key chain. Jerry plans to secretly sterilize his girlfriend’s mouth, but despite his attempts, he just can’t get past the vision of the toothbrush in the toilet. George theorizes that he may have lost his keys when he did a broad jump over a pothole that has now been paved over. Kramer works diligently to keep his part of the road clean, not trusting the work to the city’s maintenance crew. Elaine schemes to get her Chinese food by moving into a janitor’s closet, located in the building across the street. The building’s superintendent believes her to actually be the janitor and pesters her about the maintenance that needs to be done. Jenna finds out about the toothbrush and sticks something of Jerry’s in his toilet, refusing to tell him what it is.
Kramer repaints the four-lane highway to two extra-wide lanes, intending to make it more luxurious (a “two lane comfort cruise”, as he puts it), but his efforts only result in mass confusion and congestion on behalf of the drivers. George, unwilling to pay the city maintenance crew, dons construction gear and takes a jackhammer to the pothole in order to reclaim his key chain. Elaine has the gang over for dinner in the janitor closet. Jerry throws out nearly everything he owns, suspecting that anything could have gone in the toilet; he finally learns that the mystery item was nothing more than his toilet brush. George accidentally strikes a water main while digging up the road, causing an eruption that sends water bursting out of Jenna’s toilet, soaking her. Elaine, still acting as the janitor in order to allay any suspicion, brings the building’s garbage to the dump in Jerry’s car, swerving all over Kramer’s luxurious two-lane highway and unknowingly dropping an old Singer sewing machine on the road. Kramer attempts to return the highway to its original state, but spills paint thinner all over the pavement. Newman drives by in his mail truck, delivering crates of fish for the Chinese restaurant’s Supreme Flounder orders. His truck catches Elaine’s sewing machine and drags it along the highway, sending up sparks that ignite Kramer’s paint thinner and causing his truck to go up in flames as a panicking Newman shouts, “Oh, the humanity!” Kramer having witnessed the accident is desperate to evade the law, attempts to give a now torched and stranded Newman a ride, but he is stuck wandering off in a daze, so Kramer is forced to flee without him.