People do a lot of praying in this long-gestating sequel to “The Best Man,” frequently dropping to their knees and clasping their hands in supplication for divine assistance. Sometimes the pose is played for a laugh, but for the most part it’s portrayed very seriously, and often what people are praying for is literally a matter of life and death. Still, while it might seem a little cruel to say so, it would have been wise had they beseeched God for a better script than the one writer-director Malcolm D. Lee has fashioned for this belated follow-up to its 1999 predecessor. “The Best Man Holiday” is a visually spiffy but narratively flabby ensemble piece that veers uneasily from raucous farce to mawkish melodrama, managing to hit virtually every stop in between along the way. It’s an alternately coarse and sappy misfire.

The earlier picture, of course, was a wedding story, but one that had an edge deriving from the fact that best man (and aspiring novelist) Harper (Taye Diggs) had once enjoyed a one-night stand with the bride-to-be, Mia (Monica Calhoun), and was concerned that groom Lance (Morris Chestnut), his dearest friend and a superstar football player, would find out about it. The trio—along with Harper’s current girlfriend Robyn (Sanaa Lathan)—were surrounded by other members of their circle, including Jordan (Nia Long), a college classmate with whom Harper also had a fling, and who’s now a big-time TV producer; Quentin (Terrence Howard), a cynical womanizer; and Julian (Harold Perrineau), a nice guy who puts up with his harridan girlfriend Shelby (Melissa De Sousa) until he falls for Candy (Regina Hall), an ex-stripper with a tender side.

For those who don’t remember all these folks, Lee offers a montage of footage from the first film reintroducing them—a tactic that will work for those who saw the original, but is too rushed and chaotic to make much of an impression on those who haven’t. Suffice it to say that they’re all back for “Holiday,” which finds them reassembling after fourteen years to celebrate Christmas at the palatial mansion of Lance, Mia and their impossibly well-behaved children. The only new adult character added to the mix is Brian (Eddie Cibrian), the suave businessman Jordan is now dating. The crux of the plot comes from the continuing coldness between Harper and Lance, who’d found out about his friend’s dalliance with Mia and has never forgiven him (he’s also on the verge of retiring from pro football, perhaps after setting a new rushing record). That’s complicated by the fact that Harper, who’s fallen on hard professional times, is hoping for Lance’s participation in an autobiographical book that could save his career, and by the fact that a character close to them both proves to be seriously ill. As if that didn’t provide enough drama, Julian, now the headmaster of a demanding charter school, is facing a loss of funding from prudish donors after a video of Candy’s previous life is posted on the Internet, and Robyn is prodigiously pregnant. Ad-man Quentin, meanwhile, intrudes periodically to make nasty remarks, especially to Shelby, now the star of a “Real Housewives” show, with whom he once had an affair that resulted in a child.

In fact, it’s the cattiness that dominates the first half of the movie as the old chums bring up past misdemeanors and ancient grievances while simultaneously trying to put a happy face on things (including one strange scene in which the four men do what’s supposedly an impromptu air band dance to New Edition’s “Can You Stop The Rain?”) and engaging in some sassy romantic hijinks and a bit of silly slapstick involving misplaced cell phones. In the second hour the script moves into darker territory involving terminal illness and painful reconciliation. But even here it mixes in lighter moments, most notably the inevitable sequence that’s been laboriously set up by Robyn’s pregnancy. By the end the friends have lived through both joy and tragedy together and emerged closer than ever, and a postscript even sets up the possibility of a sequel should one be warranted.

“Holiday” boasts an attractive cast, and they and the locations look good—thanks to Keith Brian Burns’s production design, Aleks Marinkovich’s art direction, Michael Madden’s set design, Peter Nicolakakos’ set decoration, Danielle Hollowell’s costumes and Greg Gardiner’s cinematography (even if the exteriors don’t really resemble New Jersey in December)—but the jarring tonal shifts don’t give the performers a solid grounding to work from. Coming off best are Howard and De Sousa, who are really caricatures anyway (and get most of the best lines), and Perrineau remains an amiable presence. Diggs tries hard to sell Harper’s crisis of confidence but comes up short, and Chestnut is reduced to a lot of pouting and posing; he’s also undone by a ridiculous sequence featuring his last pro game and an overwrought funeral scene. Among the females, Long comes off best as a career-driven professional woman, though Calhoun plays the sympathy card pretty effectively and Lathan is okay.

“The Best Man Holiday” probably would have worked better if Lee—whose career since 1999 has been a pretty rocky one—had chosen to go for either drama or comedy instead of trying to juggle the two, something that results in an uneasy blend. Such a decision would also have helped streamline the picture, which clocks in after multiple climaxes at over two hours. Real reunions usually go on too long, but there’s no reason for a cinematic one to follow suit.