Homer is fired from his job as technical supervisor at the Springfield Nuclear Power Plant. Unable to provide for his family, he contemplates ending it all - until he discovers a new life path as a campaigner for safety.
The episode begins in front of Springfield Elementary, as Mrs. Krabappel rounds up her class, including Bart, and prepares them for a field trip to the nuclear power plant. Otto, the bus driver, pulls up to the curb, and Bart chats with him outside of the bus, as the other kids find their seats. Mrs. Krabappel yells at Bart to get on the bus. When he scurries to find a seat, he is bummed to see the only one left is right next to Wendell, who is always queasy and pukes on every bus ride. As Otto takes the long way to the power plant, Bart struggles to behave on the bus ride. Mrs. Krabappel warns Bart that one more outburst will result in him singing to the class at the front of the bus. Sherri and Terri, who are sitting behind Bart, decide to get him in some more trouble. At the same time, they both kiss Bart on the cheek, causing him to yell out. Mrs. Krabappel asks Bart why can't he be more like Sherri and Terri and then makes good on her threat and forces Bart to sing in front of the class. The bus finally arrives at the power plant, and Bart congratulates Wendell for making the whole bus ride without puking, by slapping him on the back, which results in Wendell vomiting anyway.
Once inside the plant, Mr. Smithers shows a film on nuclear energy in a small theater. The film stars Smilin’ Joe Fission, a little animated character, who explains the ins and outs of nuclear energy. After the film Smithers gives a tour of the plant. As the children walk behind and listen, Sherri and Terri tell Bart about how their dad, who also works at the power plant, says that Homer is an incompetent worker. Cut to Homer, who is sitting in a small motorized cart with his feet propped up, and eating a doughnut. Homer comments to a co-worker that Bart’s class will be here any minute, and he drives off in search of him. The children continue their tour, while walking on a catwalk above the working area of the plant. Just then, Homer turns the corner in his cart, underneath Bart and the other kids. Bart spots Homer and calls out to him, as Homer looks up to wave back at Bart he doesn’t pay attention to where he is going and crashes into a vent pipe causing it to leak dangerous gas. The supervisor nearby, who happens to be Sherri and Terri’s father, demands to know who caused the accident. When all the workers point at Homer, the supervisor tells Homer he is fired. He then looks up and sees Sherri and Terri and waves, and they wave back as a humiliated Bart hides his face.
The next morning at breakfast, everyone gives words of encouragement to a depressed Homer, on finding a new job. After hearing what they all have to say, a reenergized Homer heads out to find a job. But, after a long day of doors slammed in his face and no new job prospects, Homer relieves his stress at Moe’s Tavern. As Homer drinks a beer, the phone rings, Moe answers it, and it is Bart playing a prank phone call. Homer reaches for his wallet to buy another beer, only to discover he doesn’t have any more money, and when Moe won’t run Homer a tab, Homer heads for home. Later that night in bed with Marge, Homer expresses his concerns about finding another job. Marge consoles him and tells Homer that for the time being she can go back to the old job she had before they got married, as a waitress.
The next day with Marge gone at work, a depressed and unresponsive Homer lies on the couch. Even when the kids try to cheer him up he does not respond or move. Later that night, after seeing a Duff beer commercial, Homer finally gets up from the couch. Homer wanders into the kitchen and searches the fridge for a beer; he becomes enraged when he can’t find one. He heads up to Bart’s room and while Bart sleeps, Homer steals his piggy bank. Back downstairs in the kitchen Homer smashes open Bart’s piggy bank only to find that Bart doesn’t even have enough money for just one beer. Homer suddenly realizes what he has done and how low he has sunk and decides solve his problems by committing suicide. Homer writes the family a farewell note, and heads outside. In the backyard, with intentions of jumping off a bridge, Homer ties one end of a rope around his waist and the other end around a large boulder. A tearful Homer looks back at the house one last time and then struggles down the road alone, with the boulder in his arms.
Homer continues on his journey to the bridge, while back at the house Bart and Lisa rush in to Marge’s room and wake her up, telling her they’ve been robbed. Bart thinks they’ve been robbed because his piggy bank is stolen, but then Lisa discovers Homer’s note and everyone gasps. Cut back to Homer; as he nears the bridge, he crosses an intersection without a stop sign and is nearly struck by and oncoming car. Homer continues on to the bridge, and just as he is about to jump into the water below, Marge and the kids, running behind Homer, shout from a distance and tell him to stop. As they rush over to Homer, they cross the intersection and are also nearly hit by a car. But Homer quickly runs in and pushes them out of the way. He comments on how dangerous the intersection is and how someone should put a stop sign there, suddenly a light goes on in Homer’s head and he realizes that he now has a purpose in life to make the intersection safer.
The next day at City Hall, Homer presents his proposal for a stop sign at 12th and D Street, the dangerous intersection. His proposal is accepted and a stunned Homer feels a greater sense of purpose and decides to go on a campaign to make all of Springfield safer. A montage of newspaper headlines ensues, chronicling all of Homer’s new signs and his growing public support. Later the next week, after the town has been covered with safety signs, Homer still feels he must do more and decides to take on the nuclear power plant and attempt to make it safer. The next day at in the power plant, in front of a large cheering crowd, Homer stages a protest about the lack of safety at the power plant. Mr. Burns glowers down at the protest from high above, through his office window, and orders Smithers to bring Homer to him to talk privately. Smithers goes down to the protest, retrieves Homer and sends him to Mr. Burns’ office. Once inside, Mr. Burns offers Homer a new job at the plant as the safety inspector. Homer mulls over the job offer and accepts. Mr. Burns tells Homer that his first duty is to step out on the balcony and lie to the crowd and tell them the power plant is safe. Homer reluctantly steps on the balcony to lie to the crowd and suddenly has a change of mind; he heads back into Mr. Burns’ office and tells him he can’t do it. Mr. Burns realizes that Homer is very passionate about safety and won’t back down to anything; he keeps Homer on as the safety inspector anyway. Homer goes back out to the balcony to announce to everyone his new job, the crowd cheers and Homer does a celebratory dance on the balcony ledge. However, Homer, the safety inspector himself, falls off the balcony. The crowd catches him below, and they carry him off on their shoulders, chanting his name.
The cartoon at the power plant was given an old-time reel footage feel by having the animation cells dragged across a cement floor to scratch it up. This trick was used several times by the animators for the next 10 seasons.
This episode marks the first appearance of Mr. Smithers. His skin color was actually black instead of yellow. According to David Silverman, Gyorgi Peluci, the person who did the color styling randomly decided the ethnicity of various characters, which usually wasn't much of a problem, but it sort of ruined the white sycophant personality for Smithers. In his next appearance, he was colored right, but still with blue hair. Although Mr. Burns was seen in Simpsons Roasting on an Open Fire, this was his first appearance in order of production codes (as well as the first use of his name), hence the dramatic music when the camera pans out on him.
Warren Martyn and Adrian Wood, the authors of the book I Can't Believe It's a Bigger and Better Updated Unofficial Simpsons Guide stated that "the story rather fizzles out at the end, but there are many good moments, especially in the power plant."