In a world of sentient robots, striving young inventor Rodney Copperbottom (Ewan McGregor) wants to work for the avuncular Bigweld (Mel Brooks), whose Bigweld Industries makes spare robot parts. But Bigweld has just been deposed as company head by the villainous Phineas T. Ratchet (Greg Kinnear), who wants to make all robots submit to profitable forced upgrades. In this animated adventure, Rodney and his friend Fender (Robin Williams) go underground to fight Ratchet's evil plans.