In a world populated by sentient robots, Rodney Copperbottom, son of Herb and Lydia Copperbottom from Rivet Town, is an aspiring young inventor who idolizes Bigweld, a famous inventor, entrepreneur, and philanthropist whose company, Bigweld Industries, hires other inventors and provides robots with spare parts. Following Bigweld's example to "see a need, fill a need", Rodney develops a small, flying robot, named Wonderbot, to assist his father, who works as a dishwasher at a restaurant in town. When Herb's supervisor confronts them, Wonderbot malfunctions and wreaks havoc in the kitchen, leaving Herb in debt. To help Herb pay for the damages, Rodney decides to move to Robot City, hoping to present Wonderbot to Bigweld Industries in order to get a job there. Upon his arrival at Robot City, Rodney is ejected from Bigweld Industries by the company's current head Phineas T. Ratchet, who in Bigweld's absence has stopped producing spare parts in favor of expensive "upgrades", thereby "outmoding" robots who are unable or unwilling to pay for them. Ratchet's mother, Madame Gasket, runs the Chop Shop, a place that collects scrap and spare parts (and sometimes outmoded robots) and melts them to create ingots for Upgrades.
