Valiant (voiced by McGregor) is a brave little wood pigeon who's aching to join the ranks of Britain's heroic WWII homing pigeon squad. When a dashing war hero (Laurie) blithely encourages him to go for his dream, he wings his way to London, links up with a bug-infested Trafalgar Square pigeon (Gervais), and the next thing they know they're going through six weeks of rigorous training, followed by a dangerous mission to France. There they must elude a villainous German falcon (Curry) to rescue a kidnapped comrade (Cleese) and get home with a vital message.

While the basic plot isn't terribly surprising, filmmakers fill the story with all sorts of unexpected twists and turns, adding detail and humour in every conceivable place. It's not the rapid-fire cleverness of a Pixar script, nor is the animation as technically amazing, but it's so full of heart and spirit that you can't help but love it. And for every lame clunker of a gag (the French resistance contact, a sexy female mouse, is named Charles De Girl), there's a bit of inspired wit that keeps us giggling for several minutes (such as the way Williams' nurse reacts when Valiant brings her a daisy). And the historical setting adds greatly to the whole thing.

The voice work is solid. McGregor and Williams handle the bland leading roles nicely, leaving the colourful hilarity to the more outrageous characters. Cleese and Gervais are the most instantly recognisable, and they're very funny. While Broadbent as the blustering, demanding drill sergeant is the best surprise. The animation is inventive and constantly moving--full of details that liven up the slightly mundane plotline. And the script smartly refuses to talk down to children, aiming its humour at the grown-ups (well, the children inside us) and actually informing us about a little-known aspect of the Allied war effort. Great fun.