Sheryl Lee Ralph, Megan Mullally and Bruce Greenwood also star in the Key West-set feature from director Jocelyn Moorhouse.

Whether they travel in groups of three or four, accomplished women of a certain age and their wacky adventures are having a movie moment. The latest entry in this subgenre is a frothy outing that sometimes falls flat, but at least The Fabulous Four doesn’t oversell its theme of friendship or its aha moments of catharsis.

Director Jocelyn Moorhouse is no stranger to powerhouse female casts, with varied results (How to Make an American Quilt, The Dressmaker). Here she mainly steps out of the way of her stars and lets them shine, though it isn’t until the final half-hour that the proceedings hit their stride. This is especially evident when the story’s faint undercurrent of Shakespearean mistaken identity is brought into the glaring light, in a sequence that’s played, shot and framed to perfection (Roberto Schaefer is the DP). For a good share of the hijinks, the screenplay by Ann Marie Allison and Jenna Milly deploys gags that rely far too much on TikTok and THC gummies (because it’s funny when boomers use them?).

And there’s the absurd deception concocted by Kitty (Ralph), a botanist finding her entrepreneurial groove with cannabis edibles, and Alice (Mullally), a rock singer with a deep appreciation for Kitty’s wares. Their mission is to lure heart surgeon Lou (Sarandon) to Florida for the festivities because Marilyn very much wants her there, even though the two women haven’t spoken in many years, since Marilyn hooked up with Lou’s boyfriend when they were in their 20s. That she went on to build a life with him, for nearly half a century, is a seriously complicating factor.

It turns out that Lou, a Hemingway fan and a cat lover, is also remarkably gullible. And so she boards a flight south with her friends in the belief that they’re taking her to collect the six-toed cat she’s won from the Hemingway museum. It’s a ruse that necessarily crumbles within minutes of the three friends’ arrival at Marilyn’s palatial waterfront home.

Cue the wedding-preliminary this and that, the roving bacchanalia of drinking and partying and parasailing, with Marilyn’s fiancé steering clear by design (his and the screenwriters’), so as not to intrude on the girls’ weekend. And cue the awkwardness and accusatory silences between Marilyn and Lou, the latter reluctantly sticking around for the big celebration but keeping her wary distance in the meantime. Along the way, she meets two fetching men: bar owner and super-flirt Ted (Bruce Greenwood) and twinkly-eyed, Hemingway-quoting ship captain Ernie (Timothy V. Murphy). Sarandon is terrific at signaling the flushed, girlish self-consciousness that their attention, Ted’s in particular, ignites in Lou.

There are less subtle messages in a subplot involving Kitty’s ultra-narrow-minded daughter, Leslie (Brandee Evans), who’s eager to book her vibrant mother into a church-run nursing home, and the enthusiastic male stripper (Kadan Well Bennett) who turns out to be someone close to both women. Alice, meanwhile, is on a nonstop libidinous journey through this life, finding a younger man to meet her needs wherever she goes. Her personality comes through loud and clear, but however lovely Mullally’s singing voice, Alice’s bona fides as a successful and famous recording artist — one who’s recognized by a cameoing Michael Bolton — are lost in the mix. It’s Mullally’s virtuoso comic delivery that clicks here, and the way she and the equally adept Ralph play off each other (with editor Gabriella Muir’s deft work in sync with their back-and-forth).

Refreshingly, a Greek chorus of Zillennials — Renika Williams, David Goren and Abigail Dolan as the wedding party Lou meets on her flight to Florida — cheer Lou on, in both TikTok and real-world terms, as the characters’ respective adventures crisscross the island.

Midler’s Marilyn remains something of a ditzy cipher for much of the movie, in ways that sometimes leave the performance floundering but ultimately make sense. It’s at once weird and cogent that Marilyn’s TikTok obsession — incessantly recording and posting proof of her fabulous existence — is more alarming to Alice and Kitty than the fact that she’s marrying someone she’s known only a few months. In the final stretch, when Marilyn falls apart in a way that’s both private and spectacular, the method behind her busy, empty madness makes perfect sense — and, without making a fuss of it, the screenplay addresses the suddenness of her marriage plans.