The kids at Springfield Elementary take a field trip to the Nuclear Power Plant, where Homer works. However, while trying to impress Bart, he causes an industrial accident and loses his job.He writes a suicide note for his family and leaves. Lisa finds the note and the family rush to save him. Crossing a bridge, they are nearly run over by a lorry, but are saved just in time by Homer.
He campaigns to make Springfield a safer place, and eventually goes after the plant he was fired from, starting a protest outside the plant.
Angry at the uproar, Mr. Burns calls Homer into his office, and offers him a new job as safety inspector. Homer takes it.