The Muppets: Inspirational, celebrational!

It's hard out here for a Muppet.

The old gang has long since broken up. Their once-loyal fans have moved on to newer, shinier, hipper forms of entertainment. Fozzie Bear makes ends meet as part of a dreary "Muppet tribute band," called the Moopets, at a run-down casino in Reno. Miss Piggy seems to have found success as the "plus-size editor" of Paris Vogue, but her only real source of joy comes from a plate of glazed doughnuts.

And Kermit the Frog -- poor, poor Kermit, he lives all alone in the house in Beverly Hills once meant for him and Piggy, surrounded by vestiges of his former glory, wracked by regret that he has kept in such poor touch with his friends.

Ingeniously written by Nicholas Stoller and Jason Segel (who also plays one of the human roles), The Muppets finds an excuse to bring them all back together: An evil entrepreneur named Tex Richman (Chris Cooper) is about to take over the now-derelict Muppet Studios, with plans to tear it down and drill for oil below; the Muppets have just two days to bury hatchets, raise $10 million in a hastily staged telethon and salvage their legacy.

But in an era where franchises seem to get rebooted even before the first installment has been issued on DVD, this resurrection feels pure, organic and joyful. It also functions as a thoughtful exploration of nostalgia, a movie that aches for a Golden Era even as it quietly holds out hope for a brighter tomorrow.

The story is set in motion when the human Gary (Segel) and his puppet brother Walter set off to Los Angeles with Gary's long-suffering girlfriend, Mary (Amy Adams). The ostensible purpose of the trip is to celebrate Gary and Mary's 10th anniversary, but Walter's obsession with the Muppets soon takes over. When they find Muppet Studios in ruin, and overhear plans of Richman's evil scheme, they race to find Kermit and set things right.

The first thing that strikes you about the film is that the script is so perfectly plugged into the sensibility of the Muppets as typified by the classic television series The Muppet Show (1976-1981), and the first three Muppet films, The Muppet Movie (1979), The Great Muppet Caper (1981) and The Muppets Take Manhattan (1984).

The world of The Muppets is one that makes no distinctions between "adult entertainment" and "children's entertainment." Instead, it's a deliriously off-kilter, showbiz-obsessed playland, where recalcitrant frogs resist the advances of undeniable pigs, where self-referential jokes wink so aggressively at the audience that you're afraid someone is going to lose an eye, and where the musical numbers feature chickens clucking their way through Cee Lo Green's F--- You.

But much more than just an affectionate reimagining of familiar Muppets routines, the movie is rooted in real emotions and characters. No one in the film seems to be able to understand why the Muppets lost their luster, just as Piggy and Kermit seem unsure why their relationship hit the skids. But as the team rejoins forces -- and even kidnaps an unwilling celebrity to be a guest host -- their dampened spirits gradually spark back to life. The movie shows us how, whether through carelessness or ego or just plain fear, we allow a good thing to get away from us. With the character of Walter, who has dreamed of joining the Muppets all his life, the film also asserts the importance of seizing your moment.

I suppose one could gripe that the subplot about Mary and Gary's rocky relationship feels a little tacked on -- a contrived ruse to get a female star into the movie. But in the generous spirit of The Muppets, I'd rather dwell on the things director James Bobin (who created the TV series Flight of the Conchords) and his team get spectacularly right. The puppetry and voice work are as seamless and transporting as ever. The human actors, especially Segel and a host of better-if-you-don't-know-who-they-are celebrity cameos, know when to ham it up and when to play second fiddle to their furry co-stars. The musical numbers are equal parts exuberant and deranged. ( Man or Muppet and two equally terrific new compositions, Life's a Happy Song and the Miss Piggy/Mary duet Me Party, were written by Bret McKenzie, also from Flight of the Conchords.)

Mostly I'm in love with this movie's big-spiritedness and sunshiny optimism and its insistence on the "third greatest" thing life can give you: laughter. (The first and second are children and ice cream, natch.) Even when the Muppets are being ironic -- breaking the fourth wall and commenting on the very movie they're starring in, for instance -- there's nothing remotely cynical about them.

They remain as committed as ever to doing what Muppets do best: putting on a grand show.