Homer hates the new calisthenics workout program at the power plant, so he decides to become disabled in order to get out of it. After trying so many dangerous things to get on disability, he discovers that he can accomplish his goal if he gained 61 pounds. Lisa tries to convince Homer to cancel his disability task, but fails. Surprised that Homer wants to gain so much weight, Dr. Hibbert refuses to help him. Dr. Nick gives Homer advice on how to become disabled quicker, advising him to eat from the chocotastic food group. Bart wants to help Homer reach 300 pounds, and therefore assists him in eating so many unhealthy foods (and Maggie's Play-Doh doughnut to speed up his goal. Just before he has to leave for work, Homer steps on the bathroom scale for about the third time, and discovers that his weight is now over 300 pounds. Mr. Burns, now qualifying Homer as disabled, installs a computer system in his house so that he can work at home. For his first day of working at home, Homer goes shopping and buys himself a muumuu. Noticing that her father is lazier than ever on disability, Lisa tells Marge to do whatever it takes to get the new obese Homer to go back to the way he was. Marge, now feeling less attracted to Homer, tries to convince him to give up his life on disability, but he angrily refuses, saying that the slim Homer she knew is gone forever. While Marge leaves the house, Homer decides to go to the movies, leaving his computer duties in the beak of a bird. Suddenly, the plant's tank has reached critical, and it must be shut down manually. Homer rushes to the plant in an ice cream truck, and climbs the ladder to get to the manual shutdown control switch, but the catwalk splits because of his weight.
The tank suddenly explodes and Homer falls into it, preventing the gas from being let out. Mr. Burns is admired by Homer's work, and offers to do him any favor he wants. Homer, having decided that a life of disability is no longer what he desires, asks Mr. Burns to help him become his old thin-self. When Homer is unable to do just one sit up, Mr. Burns tells him that he'll pay for liposuction, and Homer suddenly cheers.