Buoyant spirit

As success follows success for animation powerhouse Pixar, the pressure to maintain the streak must be phenomenal. Will the next film be the one that stumbles, the one that breaks stride? No one need worry, however, about “Up,� Pixar’s 10th and latest effort. It’s not only good, it’s one of Pixar’s best. Some films are an obligation to write about, “Up� is the purest pleasure.

Though films such as “Toy Story,� “A Bug’s Life,� “Toy Story 2,� “Monsters, Inc.� and “Wall-E� are tough to compete with, director and co-screenwriter Pete Docter, a Pixar veteran who had a credit on all those films, was able to push “Up� into the pantheon. He did it by letting his imagination fly away. Working with co-director and co-writer Bob Peterson, Docter came up the idea of cranky 78-year-old Carl Fredricksen (voiced by Ed Asner) floating off to parts unknown when his house gets hoisted into the air by exactly 20,622 helium balloons. Try pitching that idea to your agent.

But what makes “Up� stand out is not just that core concept, but what the Pixar team has been able to do with it. Rarely has any film, let alone an animated one powered by the logic of dream and fantasy, been able to move so successfully -- and so effortlessly -- through so many different kinds of cinematic territory.

Because “Up� is a Pixar film, it’s a given that it’s going to be clever and playful. But “Up� also has the high excitement of an adventure story and enough genuine menace to make it only the second Pixar product (after “The Incredibles�) to be rated PG instead of G.

There’s also the wordless visual magic of that floating balloon-powered house as well as a truly wacky sense of humor involving a pack of dogs equipped with high-tech collars that turn their classically canine thoughts into words.

As if all this wasn’t enough, “Up� also generates genuine emotion and it does so by dealing unapologetically with one of Hollywood’s last and most persistent taboos, old people. Instead of a Clint Eastwood-type senior citizen who is fitter than people half his age, “Up� gives us a man who uses a walker and can’t handle stairs but still manages to be heroic when it counts.

And “Up’s� multi-minute montage of the long married life of Carl and his wife, Ellie, is a small gem that will stay with you for a lifetime.

Before we get to the old man, however, we meet the boy he outgrew. Young Carl is introduced in a movie theater watching a newsreel of his hero, the great South American explorer and adventurer Charles F. Muntz (voiced by Christopher Plummer), a dashing sort given to piloting his own dirigible to such exotic locales as South America’s Paradise Falls.

On the way home, Carl runs into a feisty, irresistible gap-toothed girl named Ellie (a wonderful Elie Docter, the director’s daughter) who is as enamored of Muntz and his “Adventure is out there!� motto as Carl is. Carl is happy to bask in her energy, not only for the day but for a lifetime.

The bulk of “Up,� however, takes place after Ellie’s death, with Carl as a cantankerous widower with bushy eyebrows over square black glasses and a squarer jaw.

He is so alone now, not only emotionally but also physically -- the little house he and Ellie shared is totally surrounded by an enormous modern high-rise development.

When circumstances seem to be forcing Carl out of the house he loves, he takes the kind of drastic action open to a former balloon salesman: he pumps up the helium and off he goes, heading for Paradise Falls, he hopes, and the kind of adventure Ellie always dreamed of but never had.

There’s just one problem, though: He has a stowaway. That would be an 8-year-old Wilderness Explorer named Russell (voiced by Jordan Nagai), a roly-poly package of chubby determination who is nothing if not resolved to get the “assistance to the elderly� merit badge he is in desperate need of.

Pesky, persistent and goofy, Russell is, no surprise, the perfect foil for Carl’s crankiness. Together they head off on a series of adventures neither of them could have predicted.

After all, who predicts talking animals, a giant multicolored bird who loves chocolate and a dog named Dug (amusingly voiced by co-director Peterson) who just wants to belong?

Though “Up� does so many things so well, the quality that stays with you longest is its fearlessness in the face of emotion. This is a film that is heartfelt enough to restore your faith in whatever needs restoration. --

‘Up’

MPAA rating: PG for some peril and action

Running time: 1 hour, 30 minutes

Playing: In general release