In "Flushed Away," Aardman Features, the U.K.-based cartoon studio that has achieved world renown for its stop-motion animation, jumps daringly and with great success into a brand new style.

The movie, a wonderfully chaotic affair nimbly directed by David Bowers and Sam Fell, is entirely computer animated yet retains the Aardman "look" as the characters are designed as if they were plasticine puppets with the expressive brows and exaggerated mouths one associates with its films. Collaborating with DreamWorks Animation, for whom the studio already has made "Wallace & Gromit: The Curse of the Were-Rabbit" and "Chicken Run," Aardman has turned out a gloriously droll comic adventure that combines British wit with Yankee exuberance.

There is no age limit to this movie, which might need multiple viewings to catch all the background gags and snappy one-liners that rush at the viewer with a vaudevillian sense of gleeful anarchy. "Flushed Away" appears primed to make the cartoon studios and Paramount flush with money.

Roddy St. James (Hugh Jackman in full Roddy McDowell form) is a pampered pet mouse in the posh Kensington neighborhood of London. His space is invaded by a lower-class sewer rat named Sid (Shane Richie), while his family is on holiday. Roddy's scheme to lure his rival for the pleasures of the household into a toilet for a "whirlpool bath" backfires when Sid, wise to the ploy, flushes Roddy down instead.

Roddy winds up underground in an alternate version of London, comprised of discarded items that replicate well-known landmarks and teeming with mice, rats, frogs and slugs. Almost immediately, Roddy gets embroiled in the nefarious misadventures of a red-headed tomboy rodent named Rita. Kate Winslet takes that name to heart, giving the character a hip London accent and the confident street smarts that remind you of many of Rita Tushingham's roles in British films from the 1960s.

Rita captains her own sewer boat called the Jammy Dodger, aboard which a gas can serves as a cabin, water tap for a helm and green tennis balls for side bumpers. Rita is locked in mortal combat with the villainous Toad (Ian McKellen), who hopes to rid his world of rodents yet employs two as his henchrats, the all-talk-little-action Spike (Andy Serkis) and a haulking albino rat named Whitey (Bill Nighy).

A struggle over a ruby diamond devolves into a battle for a piece of cable Toad needs to fulfill his dastardly plan to wipe out the cheese-eating underground population. When his henchrats come up empty, Toad calls on his cousin Le Frog (a hilarious Jean Reno), a French mercenary who means business but only after a five-hour dinner.

A wild river chase through the sewers is the film's highlight, but really once Roddy gets flushed underground the action is more or less nonstop.

Sound effects and music play key roles in the comedy. Noises and sounds are familiar yet spring from unexpected sources. Song cues drift in from singing slugs. These colorful, tiny, blob-like creatures burst into pop songs that comment deliciously on the action, joining in with Roddy at one point in serenading Rita. They come very close to stealing the picture from the rodent heroes.

In truth, all the characters are brilliantly conceived both in terms of their physical form and their strong personalities, from which rich comedy is developed by writers Dick Clement, Ian La Frenais, Chris Lloyd, Joe Keenan and Will Davies (from a story by Fell, Peter Lord, Clement and La Frenais).

The characters are not as elastic as is typical in CG or, for that matter, even old-fashioned cel animation. The figures are designed to move and behave as if they were made of clay, wood and paint. They pose and use facial expressions with a heavy emphasis on the Aardman trademark of brows and mouths.

The backgrounds, witty takes on the contemporary human world, are colorful and meticulous in detail. Harry Gregson-Williams' rollicking score gives a huge lift to all the comedy.