Planet Earth is a dump. Literally.

In the 28th century, the human race has fled to space, and apart from a few cockroaches, there are no life forms to speak of, just empty metropolises, abandoned ultra-malls and mountains of debris festering in the toxic haze of a long-ago environmental meltdown.

What's a lonely robot to do?

Well, in WALLE, the little rusted box with the binocular face and tank treads for feet falls in love, that's what.

An adventurous shift away from the anthropomorphic madcappery of Pixar's recent animated features, WALLE, directed by Finding Nemo and Ratatouille veteran Andrew Stanton, is part love story, part eco-cautionary tale, and, for its first half, pretty much devoid of human dialogue.

Instead, there are the expressive pings and squeaks of the title character, a kind of sad-sack R2D2 left on Earth hundreds of years earlier to clean up the place. Which WALLE (Waste Allocation Load Lifter Earth-Class) is still busy doing, dutifully making skyscrapers out of crushed metal and stashing some of the kitschy detritus of yesteryear - garden gnomes, rubber duckies, old VHS tapes - in his metal shoebox of a home.

And then one day a pulsating little object that looks like a cross between an iPod and one of those Dollar Store pocket fans flits down from a spaceship. Its EVE (or Extra-terrestrial Vegetation Evaluator), sent to suss out whether our world is possibly habitable again.

Over the course of a few days and star-gazing nights, watching clips from the 1969 Hollywood musical, Hello, Dolly!, WALLE and EVE beep and squeak at one another, loll around, communicating as best they can. It's robot romance for sure.

With rich, detailed, cinematic animation and terrific sound effects, WALLE pulls this unlikely love story off. But then, when EVE discovers an actual living plant on Earth and carries it back to her spaceship for analysis, WALLE secretly tags along, taking the duo to a galactic cruiseship peopled (yes, peopled) by obese, sedentary cell-phone-yapping humans adrift in exile. WALLE doesn't know what to make of this new, strange place, and when he encounters a bunch of "rogue" robots, shipboard mayhem ensues.

This latter part of WALLE is more traditional, and less involving, but there is still lots of cleverness - visually and storywise - to keep things going. The attention to detail - always a Pixar hallmark - is amazing, and Stanton and his crew incorporate surprising elements that mix vintage sci-fi with old musicals (the seemingly oddball Hello, Dolly! motif is nicely dovetailed into the narrative) with a meta-cartoon rendering of the future.

Don't miss the Pixar short, Presto, that runs before WALLE, either. Animator Doug Sweetland's tip of the (magician's) hat to old Tex Avery 'toons is a real treat.

WALLE *** (Out of four stars)

Directed by Andrew Stanton. With the voices of Ben Burtt, Jeff Garlin, Kathy Najimy, Sigourney Weaver and Fred Willard. Distributed by Walt Disney Pictures.

Running time: 1 hour, 37 mins.

Parent's guide: G (cartoon mayhem)

Playing at: area theatersEndText

Contact movie critic Steven Rea at 215-854-5629 or srea@phillynews.com. Read his blog, "On Movies Online," at http://go.philly.com/onmovies.