Happy Feet Two may be set in Antarctica, but it's only a lukewarm effort.

In this 3D sequel to the Oscar-winning, 2006 animated hit, the lesson all the characters learn, no matter their species, is that only when they all work together can problems -- including a shift in the glacial landscape that threatens the penguin community's very existence -- be overcome.

Or, as I seem to recall learning years ago while watching Sesame Street, the word for the day is cooperate.

Two introduces a new leading character, Erik (Ava Acres), the adorable, fluffy penguin son of the original's tap-dancing hero, Mumble (Elijah Wood). Erik is feeling blue because, unlike his dad, he can't dance, and unlike his mom, Gloria (Alecia Moore, aka the singer Pink, who takes over a role originated by the late Brittany Murphy), he's not excited by singing.

In addition to Erik and Mumble, other major characters include Ramon (Robin Williams), a boastful penguin who falls for curvaceous Carmen (Sofia Vergara); Sven (Hank Azaria), a penguin whose ability to fly turns Erik into a worshipful acolyte; Bryan (Richard Cater), a lumbering elephant seal; and Will (Brad Pitt) and Bill (Matt Damon), two tiny, shrimp-like krill who leave their swarm behind to venture out into the ocean.

The problem with Happy Feet Two is that its profusion of storylines and characters leave it feeling hectic and overstuffed but without much of a payoff. Few of the characters or plotlines have enough heft or originality to draw in a viewer. At a mere 99-minutes running time, this sequel feels like a long haul.

Which is not to say that the movie, which is again directed and co-written by George Miller (Mad Max), isn't without its charms. Real life pals and sometimes co-stars Pitt and Damon have looky-loos fun as Will and Bill, the adventurous krill, even managing a few topical jokes. When Bill suggests that the duo pair up and raise a family, Will points out that they're both male. Bill, unbothered, replies, We can adopt.

And there's a lovely, unexpected moment late in a movie when little Erik breaks out into a full-throated, soaring operatic aria (cribbed from Puccini's Tosca) in praise of his father.

For small fry viewers, the main target audience for the movie, there are pee and poop jokes aplenty, a surefire laugh getter when one is oneself only a few years past wearing Pull-Ups.