The film opens in a world of anthropomorphic robots, with Herb Copperbottom (Stanley Tucci), a dishwasher at Gunk's Greasy Spoon diner, racing through the streets of Rivet Town, elated that he is going to be a father. He and his wife, Lydia (Dianne Wiest), after 12 hours of "labor", finally manage to construct the baby. He is named Rodney (Ewan McGregor), and he becomes a young inventor who dreams of making the world a better place for everyone. Rodney idolizes Bigweld (Mel Brooks), a master inventor and owner of Bigweld Industries. During Rodney's adolescence, he invents a gadget, "Wonderbot", intended to help his father clean the dishes at the restaurant. When Herb's boss, Mr. Gunk (Dan Hedaya), unexpectedly confronts them, Wonderbot panics and begins breaking dishes, resulting in Rodney being fired. Later, he decides to take his invention to Robot City to see Bigweld and get a job as an inventor so that he can help his family. He is encouraged by his father, who confides that he has always regretted not becoming a musician. Rodney arrives in Robot City and meets Fender (Robin Williams), a ramshackle robot scraping by through taking souvenir photos (with a camera that has no film) and selling maps to the stars' homes. After a harrowing ride on the crosstown express, Rodney arrives at the gate of Bigweld Industries.
There he learns that Phineas T. Ratchet (Greg Kinnear) has taken over Bigweld Industries and is about to discontinue the manufacture of spare parts. Ratchet believes the company can make more profit if it stops making spare parts for older robots and focuses on selling more expensive upgrades. If any older robots protest they are sent to the underground Chop Shop, where they are shredded and melted down by Ratchet's imposing mother, Madame Gasket (Jim Broadbent). Rodney is thrown out and finds a place to stay, with Fender, at Aunt Fanny's (Jennifer Coolidge) boarding house, along with an assortment of other "Rusties", older robots threatened with the Chop Shop. When the news gets out that spare parts have been discontinued by Bigweld industries, Rodney remembers Bigweld's slogan, "See a need, fill a need", and begins fixing old robots on his own. Upon learning of this financial threat, Gasket orders Ratchet to stop Rodney's work and kill Bigweld.
Rodney finds that Herb has fallen ill, and can not find replacement parts. Rodney decides to try to contact Bigweld directly, so he can beg him to make spare parts again. Wonderbot reminds him that the annual Bigweld Ball takes place that night. Rodney and Fender go to the ball in disguise, only to hear Ratchet announce that Bigweld was unable to attend. Rodney tries to confront Ratchet, but is stopped by security robots. He is saved by Cappy (Halle Berry), a beautiful robot-executive of the company who dislikes Ratchet's scheme, and together with Fender and his new girlfriend, Loretta Geargrinder (Natasha Lyonne), they escape from the ball.
Fender walks Loretta home, then dances (in a take-off on the iconic dance number by Gene Kelly, "Singin' in the Rain"), but his guard is down and he is captured by one of the Sweepers and taken to the Chop Shop. He struggles to escape, losing his lower half in the process. Fender eventually escapes by reluctantly attaching a new pair of female legs. Meanwhile, Rodney and Cappy fly to Bigweld's home. When Rodney inadvertently knocks over a domino, setting off a chain reaction of dominoes, Bigweld appears. Rodney tries to convince Bigweld to return to the helm of his company and once again make spare parts available, but Bigweld refuses. Rodney calls his parents, intending to give up his ambition of becoming an inventor and return to Rivet Town, but his father again encourages Rodney to pursue his dream. Fender arrives and reveals that Gasket has built a fleet of super-sweepers with the intention of rounding up and destroying all older robots, so Rodney rallies the Rusties into fighting back against Ratchet. Bigweld eventually decides to come with the group, having realized what he meant to Rodney.
The group heads for Bigweld Industries, where Bigweld tries to fire Ratchet. Ratchet manages to beat Bigweld senseless, but Rodney and Bigweld escape. Bigweld is repaired just as they enter the Chop Shop, but is captured. A desperate battle ensues between Gasket's employees and Rodney's repaired robots. During the chaos, Bigweld is rescued by Rodney, the choppers and sweepers are destroyed, and Wonderbot kills Gasket by tossing her into the melter, while Ratchet loses his upgrades and gets stuck on the ceiling with his father. Bigweld goes to Rivet Town to tell Rodney's parents that their son is now his right-hand inventor and eventual successor. Rodney makes his father's dream come true by giving him a three-bell trumpet, playing by sheer improvisation that prompts the others to help add other musical tunes; Fender finds the new music to be a mix of Jazz and Funk — "Junk". The audience dances to James Brown's "Get Up Offa That Thing" as a victory celebration.
Voice cast Edit
- Ewan McGregor as Rodney Copperbottom, a young blue robot and aspiring inventor.
- Halle Berry as Cappy, Rodney's love interest.
- Robin Williams as Fender, an old red robot that's always falling apart.
- Amanda Bynes as Piper Pinwheeler, Fender's younger sister.
- Mel Brooks as Bigweld
- Greg Kinnear as Phineas T. Ratchet
- Drew Carey as Crank Casey
- Jennifer Coolidge as Aunt Fanny
- Harland Williams as Lug
- Jim Broadbent as Madame Gasket, Ratchet's mother.
- Dianne Wiest as Lydia Copperbottom, Rodney's mother.
- Stanley Tucci as Herb Copperbottom, Rodney's father.
- Natasha Lyonne as Loretta Geargrinder, Fender's love interest.
- Paul Giamatti as Tim
- Dan Hedaya as Mr. Gunk
- Jay Leno as a Fire Hydrant
- Lucille Bliss as a Pigeon Lady
- Paula Abdul as Wristwatch #1
- Randy Jackson as Wristwatch #2
- Ryan Seacrest as Wristwatch #3
- Al Roker as Mailbox
- John Mahoney as Ratchet's robots.
- James Earl Jones as Darth Vader, voice chip.
- Randall Montgomery as Zinc
- Jack Angel - James Hickenbottom
- Bob Bergen - Max Hickenbottom and Male Robot
- Rodger Bumpass - Eddie Hickenbottom
- Lara Cody
- Cooper Cowgill
- David Crommett
- Jennifer Darling - Yodeling Robot
- Darin De Paul
- Paul Eiding - Jerry Hickenbottom
- Bill Farmer - Rodger Hickenbottom
- Dann Fink
- Timothy Gulan
- Alexander Haney
- Ray Iannicelli
- Sondra James
- Vanessa Lemonides
- Anthony J. Lewis Jr.
- Sherry Lynn - Female Robot
- Marcus Maurice
- Mickie McGowan - Crosstown Express Announcer and Screaming Robot
- Jennifer Perito
- Phil Proctor - Charlie Hickenbottom and Mr. Nuts
- Kristin Reeves
- David Rossmer
- Lyla Stone
- Bruce Winant