Homer's half-brother Herb has been living as a bum since losing his car company because of Homer's failure of designing a car. When he gets an idea for an invention that can make him rich again, he goes to Springfield and asks the Simpsons' help to develop it, using award money that Homer received from Springfield Nuclear Power Plant.
Homer and the rest of the Springfield Nuclear Power Plant employees are summoned for the annual company physical. Homer's sperm count comes back as incredibly low, due to the radiation at the plant. Realizing that the plant could be sued for millions, Burns considers options for escaping that liability. He and his lawyers settle on the idea of tricking Homer into signing a waiver by pretending that it is an award, given in a hastily-concocted ceremony for "The First Annual Montgomery Burns Award For Outstanding Achievement in the Field of Excellence." Homer receives $2000 as the award.
Meanwhile, Herb Powell, now bankrupt and sleeping on the streets, discusses how he lost his fortune due to his half-brother Homer's stupidity (as shown in "Oh Brother, Where Art Thou?") with other homeless people, one of whom claims to be the creator of New Coke. After boldly claiming that all a person needs is a good idea, Herb sees a woman struggling to understand her baby and seizes on the idea of developing a baby translator. When Herb's fellow bums tell him that even with an idea, he's still a bum, Herb changes his claim to saying that all a person needs is an idea and some money to get it off the ground. Herb finds a newspaper with a photo of Homer winning the Burns award (and accepting the cash prize), and decides to pay him a visit to ask for a chance to make his money back.
Homer, though, has other plans for the award money. After Bart and Lisa destroy the couch during a session of "broom vaulting" in the "living room Olympics," Homer finds a store selling a vibrating chair for $2000, which he immediately falls in love with. Marge talks him out of making the purchase. Meanwhile, Herb, looking for the Simpsons, accidentally goes to the Flanders' house next door. They clean and bathe him (Todd want to cleans Herb's shoes which disappoints him when his mom takes over) and give him a new suit. Herb then goes to the Simpson home. When Homer answers the door, Herb punches him in the face and walks in.
Herb asks them for a second chance and explains his baby translator idea. Marge, Bart, and Lisa convince Homer to give him the money, even though he's still skeptical about the translator. Now with the money as well as the idea, Herb goes to work on his baby translator. After much work with Maggie, he unveils the translator to the family, who are quite overwhelmed by it despite its clunky appearance. However, the device does work, and Herb takes it to a Baby Convention, where he is innundated by orders and an offer from a baby goods store to stock thousands of his translators. Herb believes that he has made his fortune back again.
As Herb leaves the Simpsons, he repays Homer the $2000, then gives everyone gifts. To Lisa, he gives a subscription to "Great Books of Western Civilization"; to Bart, a membership in the National Rifle Association; to Maggie, a promise to get her something nice when the baby translator says she wants what the dog is eating; and to Marge, a replacement washer and dryer, plus $50 which he made from selling the old ones. Finally, to Homer, two gifts—his forgiveness and acceptance as a brother, plus the vibrating chair that he wanted so much. Homer is immensely pleased by this gift.