Chrissie Fit, Anna Camp, Alexis Knapp, Brittany Snow, Anna Kendrick, Rebel Wilson and Ester Dean in “Pitch Perfect 3.” (Quantrell D. Colbert/Universal Pictures)

I started to have a bad feeling about “Pitch Perfect 3” as soon as the a cappella version of the Universal Pictures fanfare faded away. The third installment in the popular comedy franchise about an all-female vocal group begins with an explosion aboard a yacht, as Beca and Fat Amy (Anna Kendrick and Rebel Wilson) are shown running for their lives while flames threaten — as if the duo were stuck in an off-brand 1980s cable action flick. Little good can come from a musical comedy that stoops to raiding a different genre for its humor.

Then the words “Three Weeks Before” appear.

Heed this warning, because that is how long this dirge of a money-grab sequel seems to last. What was delightfully fresh and frisky in the first “Pitch Perfect” as the Bellas — a ragtag college crew of female a cappella singers — found their groove together is now an off-key dismantling of what made the concept work in the first place.

There is not much fun to be had in learning where the group’s members have landed after graduation, since they are all struggling in the real world. This is probably the only realistic detail to be found in the script, by returning sitcom veteran Kay Cannon, with an assist from the usually spot-on Mike White (“School of Rock,” “Beatriz at Dinner”). But at a reunion, Anna Camp’s overachieving control freak Aubrey suggests that her military dad can get her fellow singers a spot on a USO tour. As quick as you can say, “shooting in Atlanta is cheaper than Europe,” off our gals go to recapture their youth. Of course, there is a sort-of competition involved. But, oh, the horror, when the Bellas learn that the three other groups competing use actual instruments.

This story line soon fades away, and what we are left with are rather canned renditions of such songs as DNCE’s “Cake by the Ocean,” Sia’s “Cheap Thrills” and Britney Spears’ “Toxic.” Elizabeth Banks and John Michael Higgins return to deliver the catty dialogue for which they are known, as Gail and John, a cappella competition commentators who are supposedly making a documentary about the Bellas’ comeback. But, really, it is just an excuse for Higgins to continue to make mock-sexist remarks about mom jeans, and to introduce the group like this: “As these women approach 30, and cease to be of value as human beings . . .”

Although Kendrick’s pint-size dynamo once pushed the Bellas beyond their la-la-la comfort zone, she basically sleepwalks through this third go-round. That leaves Wilson’s loud-and-proud belter to do most of the heavy lifting, as she discovers that her estranged father — an Australian gangster portrayed by John Lithgow, in a flat performance — has been following her every move overseas. Her big comic moment involves an elaborate outburst of martial arts moves, as she single-handedly takes down a squad of baddies. Director Trish Sie, who is known for having overseen several of OK Go’s intricate music videos, fails to make much out of the scuffles — sausages used as nunchucks? — or the accidental trashing of a pricey hotel room.

The lone musical number that lifted my spirits comes late in the film, when Kendrick’s Beca brings up her fellow Bellas to join her in a glossy rendition of George Michael’s “Freedom! ’90.” As soon as it was over, I was only too happy to seek my own freedom in the lobby.

PG-13. At area theaters. Contains crude and lewd material, strong language and some action. 93 minutes.