Homer tries everything to get out of the plant's new exercise program and discovers that being on disability would do just that. With Bart's help, Homer begins eating whatever he could get a hold of, including Play-Doh.
Mr. Burns organizes an exercise program at the power plant. Though many of the workers are impressed by this program as it keeps them fit and motivated, Homer hates it. After learning that those on disability get to work at home (and not take part in the exercises), he tries to injure himself. When he discovers that hyper-obesity counts as a disability, he chooses to put on weight until he is 300 pounds. In this way, he can be legally disabled and force Burns to let him telecommute. Despite Lisa's protests that this could endanger his health and he is abusing a program that most people would want to be a part of. While Doctor Hibbert won't help Homer, he recommends Dr. Nick who will help him. Homer engages in nearly unprecedented gluttony. After a mass eating spree with Bart, he tells Homer that they're out of food, including the basics. Faced with the prospect of another day at work, Homer eats a Play-Doh donut that Maggie made. This manages to push him over the 300 pound goal due to the Play-Doh being non-toxic (much to his excitement), but Bart notices that Homer's gut is caught on the towel bar. Once Homer lets his gut hang down, the scale readjusts to 315 pounds, much to his amazement.
A computer work station is set up in the Simpson home for Homer's position. Homer enjoys working from home and he thinks that he will get a can of Tab if he presses the "tab" key due to his stupidity. He teases Bart and Lisa because they have to go to school while he gets to stay home. Lisa says she wishes she could live at school Bart on the other hand wants to be overweight so he could stay at home and work. Lisa is starting to get annoyed by this and even goes to Marge insisting that she talk to Homer. Marge tells Lisa that while she does want to put a stop to Homer's obesity she tells Lisa that Homer can be sensitive at times and she doesn't want to hurt his feelings, but by now she may have to. Lisa tricks Homer to see Marge who then tells Homer they must discuss the pros and cons of his obesity. While Homer names a few pros such as being stout and not going to work Marge names several cons: he's endangering his health, setting a bad example for the kids, running the ac all the time and Marge is finding herself less attracted to Homer physically. While this almost changes Homer's mind, he refuses to budge and go back to normal. He then goes back to work and ends up typing "yes" to everything. Then, he realizes that all he had to do is to press "y" to answer "yes" on the computer but does not read the command correctly, so he impatiently constantly presses the "y" key. However, he soon ends up tired of the repetitiveness of the situation and begins to get distracted. Some of the kids at Bart and Lisa's school start to make fun of him and Lisa does try to defend her Dad but to no avail. Later, Homer leaves a drinking bird pressing the "y" key while he goes out to see a movie at the movie theater. After being refused to be seated due to his large 315 pound size and due to getting heckled by some people outside the movie theater, Homer returns home and is vowing to show that overweight people can be important. Upon his return, he finds out that the drinking bird has been knocked aside and that a nuclear meltdown at the power plant is imminent, he tries to turn it off, but it's so overheated he has to go to the plant to shut it off, so Homer rushes to the plant and bravely tries to take charge. He ultimately saves the day when the ladder to the manual shut-off switch collapses due to his weight. He then falls into the release tube where his enormous gut gets stuck and prevents the toxic gas from escaping. As a reward and upon Homer's request, Mr. Burns guarantees that he will make Homer slim again. Later that night, after Homer fails with his exercise program, Burns chooses to just pay for the liposuction, much to Homer's joy.