'The Muppets' reteam with mixed results

The muppet character Constantine, a Kermit the frog look-alike, in a scene from Walt Disney Pictures' 'Muppets Most Wanted'

A strange sense of doom hangs over the rebooted Muppets, and it's not from the Swedish Chef's cooking.

"The Muppets" (2011) may have been an earnest and largely successful relaunch for Jim Henson's troupe, but it also had a hangdog melancholy, fretting about the obsolescence of Kermit and the gang. Pop-culture insecurity looms in "Muppets Most Wanted," too, which begins with the same self-conscious tone as the last film in the musical number "We're Doing a Sequel."

Though Dr. Bunsen Honeydew (still the greatest name in show biz, sorry Sidney Poitier) notes this is technically the Muppets' seventh sequel, they nevertheless sing: "And everyone knows the sequel's not quite as good."

The Muppets don't need a sequel. They need a shrink. It seems they've swapped "the most inspirational, celebrational, Muppetational" show for an ongoing pity party. Where is the confident intrepidness that made Gonzo disdainful of breaking through "the easy way" (Hollywood) when you could go through Bollywood instead?

"Muppets Most Wanted," thankfully, soon enough dispatches the previous film's mopey nostalgia and sets things on a more madcap course: a European caper, not unlike 1981's (alas superior) "The Great Muppet Caper." The ingredients are here: Tina Fey as a Broadway-loving Gulag guard in Soviet chic; Ty Burrell in Inspector Clouseau mode; Ricky Gervais as the comically obvious bad guy (name: Dominic Badguy). But "Muppets Most Wanted" fails to whip up the kind of furry frenzy that makes the Muppets special.

What's missing? Many would say Jason Segel, the star and co-writer of "The Muppets." He's the holdout of largely the same, solid creative team: director James Bobin, co-writer Nicholas Stoller and music supervisor Bret McKenzie.

But the bigger problem with "Muppets Most Wanted" is a failure to find the right human-to-Muppet ratio and a screwball feel for how the species interact. Most successful are Fey (who emerges as an unlikely rival to Miss Piggy for Kermit's heart) and Burrell (an Interpol policeman paired with the CIA's Sam the Eagle).

The Muppets instead feel upstaged by the parade of celebrity cameos (they range from Lady Gaga to Christoph Waltz), as if the movie is one big selfie for stars to be seen alongside their Muppet heroes. The plot, too, doesn't yield much time to favorites like the lovingly harebrained Gonzo the Great, the endlessly chipper Fozzie the Bear or the mellow, melodic Rowlf the Dog.

The film picks up literally where "The Muppets" left off, as they disassemble the movie set. Unsure of their next step, the Muppets are persuaded by a slick British agent (Gervais) to embark on a theater tour in Europe. Only Kermit is suspicious, but he's soon kidnapped by an escaped Russian criminal mastermind, Constantine.

Constantine (voiced with a playful Russian accent by Matt Vogel) happens to look precisely like Kermit (again voiced by Steve Whitmire), only with a mole on his cheek and a slightly more pinched nose. While Kermit is mistakenly sent to the Gulag in Siberia (fellow inmates are played by Ray Liotta and Danny Trejo, as himself), his evil doppelganger replaces the Muppet leader on tour. He and Badguy use the performances as a distraction for robbing banks.

Much of the humor stems from the Muppets' failure to recognize the clearly different version of their long-legged impresario. The usually fastidious frog, with Constantine running things, doesn't mind giving Animal an endless drum solo and absent-mindedly calls Gonzo "Zongo."

Judging the Muppets against their own high standards is perhaps unfair, particularly when we've been absent of Henson's genius for nearly 25 years. "Muppets Most Wanted" may not rise to the irreverent slapstick the gang once did, but it is still, after all, the Muppets.

Yet instead of trying to be like other globe-trotting, star-studded sequels, the Muppets ought to be happy with simply being themselves. How does the song go? Keep believing.

Two and a half stars out of four.