The Copperbottoms (voiced by Tucci and Wiest) are proud of their inventor-wannabe boy Rodney (McGregor). But when he heads off to the big city to start a life as an inventor nothing goes as planned. Rodney's idol Bigweld (Brooks) is missing, his empire taken over by the greedy Ratchet (Kinnear)--who's actually driven by his ogre of a mother (Broadbent). So Rodney teams up with a motley crew of outcast robots (Williams, Bynes, Carey, Coolidge) to save the day.

There's an almost Simpsons-like density to this film, which keeps both visual and vocal jokes flying off the screen. It's a constant current of clever and witty gags, many of which are sharp throwaway bits the film never slows down for. Meanwhile, the animators wonderfully render this robotic world as a collection of nuts, bolts, oozing oil and gleaming chrome that looks absolutely fantastic on a big screen (video might be less impressive). This is an inventively realised animated universe full of tiny details. So you can forgive the filmmakers for getting caught up in the gadgetry from time to time. Some of the most technically awesome sequences actually add nothing to the plot; it's like a whiz kid just having fun with animation software. While the story is a bit boyishly technical for very young audiences.

Where the film comes together brilliantly is in the characters and storyline. There's nothing terribly original going on, but it's done with such heart and spark that you can't help but have a great time joining the adventure. The actors all smartly subvert their own personalities--although Williams goes off on a few of his gleefully goofy riffs, and Broadbent and Kinnear are clearly having too much fun. The pop culture references are sometimes rather strained, but even those moments are amusingly warped enough to appeal to the kid inside us.