As engaging as its cast is, and as infectious as their a cappella performances can be, the "Pitch Perfect" franchise has continued to fall victim to the law of diminishing returns. If 2012's "Pitch Perfect" was a delightfully savvy college comedy with a certain amount of gravitas to go along with its bubblegum-pop tone and 2015's "Pitch Perfect 2" was a lesser but still engaging variation on the same beats, "Pitch Perfect 3" sputters along with an air of warmed-over inconsequentiality. In a bid to reunite characters who have graduated and set off into the big, bad grown-up world, director Trish Sie (2014's "Step Up: All In") and returning writer Kay Cannon devise a contrived overseas adventure that does next to nothing with its timely premise of a USO tour. On paper, the idea of the Bellas singing for the troops sounds promising, a chance to give a respectful real-world undercurrent to a series that's become all about the silly. On screen, however, zero time is spent on what it actually means to bring entertainment to military people looking for a respite from the stresses of their daily lives. The Bellas are too busy with their own personal problems to consider the greater implications, while the audiences in front of them are so nondescript they might as well be randos attending their local "Concert in the Park" series.

Three years have passed since Beca (Anna Kendrick), Fat Amy (Rebel Wilson), Chloe (Brittany Snow) and most of the other Bellas graduated from Barden University. A long way from having won the World A Cappella Championships in Copenhagen, they are now floundering in careers—or no career at all, in Fat Amy's case—that haven't turned out quite like they'd imagined. When Beca loses her music producer job on the same day the gang reunites to see their collegiate pal Emily (Hailee Steinfeld) perform with the current class of Barden Bellas, Aubrey's (Anna Camp) proposal for the former musical group to travel abroad and sing their hearts out on a USO tour sounds too tempting to pass up. Relieved at first that they will finally not be in competition with anyone, the Bellas soon discover they actually are, their group and a cool female rock band called Evermoist (led by Ruby Rose) vying as potential openers for DJ Khaled. Oh, and commentator extraordinaires John Smith (John Michael Higgins) and Gail Abernathy-McKadden (Elizabeth Banks) are also on hand, following the tour while shooting what they've labeled a "dacamentary."

"Pitch Perfect 3" features an ensemble of bright comedic actors untested by their material but nevertheless appearing to have a rollicking time together. Their fun only intermittently bleeds over into the viewer. This is a decidedly listless and uninspired sequel, going through the motions of what's been done before with only a fraction of the same charm and resonance. When Sie and Cannon dare to divert from formula—there is a third-act hostage situation, a jump from a fiery yacht, and a kitchen-set fight sequence with Fat Amy—it adds a vague streak of freshness while also casting a light on the desperate lengths this franchise has gone to find new stories to tell.

Everything done so exuberantly in "Pitch Perfect" has now grown stale. There is no denying Anna Kendrick (2016's "Mike and Dave Need Wedding Dates") can light up any stage on which she appears, but creatively, the musical numbers are forgettable save for a terrific a cappella cover of Britney Spears' "Toxic" and another where Evermoist performs The Cranberries' "Zombie." The customary first-act riff-off is an inferior shadow of the ones in its predecessors. The finale disappointingly does away with a medley for a single song—George Michael's "Freedom '90"—and the results are supremely underwhelming. Never are the Bellas shown practicing as a team, or planning out their song list, as was such a valuable part of the camaraderie seen in the original "Pitch Perfect." In its place are shaggy subplots involving Aubrey wanting to sing for her busy military father, and Fat Amy questioning if she can trust her wealthy estranged dad (John Lithgow) when he suddenly walks back into her life. Meanwhile, Beca's and Fat Amy's winning relationships with Jesse (Skylar Astin, MIA) and Bumper (Adam DeVine, also MIA) are out, replaced with a few new, far less involving romances between Beca and fellow music producer Theo (Guy Burnet) and Chloe and a handsome Coast Guard private (Matt Lanter) assigned as the Bellas' USO tour liaison.

Passably diverting but altogether lazy, "Pitch Perfect 3" gives a handful of its actors a few choice one-liners—Rebel Wilson (2016's "How to Be Single") continues to be a standout as loose cannon Fat Amy, while Chrissie Fit's Guatemalan member Flo earns laughs while putting into perspective the comparatively middling problems of privilege she sees happening around her—but squanders the rest. John Michael Higgins (2014's "A Million Ways to Die in the West") and Elizabeth Banks (2015's "Magic Mike XXL"), always so tart-tongued and delightfully catty as commentators John Smith and Gail Abernathy-McKadden, are underused. Dynamite situations could have been dreamt up as this bon-mot-ready duo tag along shooting their "dacamentary" about the USO tour, but precious little is done with it and they are frequently forgotten. Meanwhile, the forever-whispering Lilly (Hanna Mae Lee) gets a ridiculously funny out-of-left-field payoff, but before this is mostly rendered a background player. As the film reaches its anticlimactic conclusion, there is the undeniable sense that the very reason for its existence is strictly of the financial variety. Beyond this, the premise is glaringly mishandled with a slapdash script in need of an overhaul. "Pitch Perfect 3" has been described in its promotional campaign as the Bellas' "farewell tour." Perhaps it really is time to say good-bye.