Like a sort of anti-“Ocean’s 8,” Steve McQueen’s long-awaited follow-up to “12 Years a Slave” is about an elaborate heist carried out by a group of women. But “Widows” is far from a happy-go-lucky lark. Loosely based by McQueen and Gillian Flynn on a British television series written by the prolific Lynda La Plante, it’s a dark, convoluted tale of crime, corruption, and abuse that’s really too overstuffed for its own good but bolstered by a committed cast.

Though LaPlante’s version was set back in 1983, the script by McQueen and Gillian Flynn (“Gone Girl”) updates the plot to contemporary Chicago. That’s one of the problems with the film, since a major element of the plot involves the city’s politics, which frankly seem more reflective of the situation in the seventies than the present day: Jack Mulligan (Colin Farrell), the son of long-time alderman Tom (Robert Duvall), is trying to win his father’s seat against black neighborhood leader (and drug lord, it appears) Jamal Manning (Brian Tyree Henry).

That story thread links up with the main storyline, involving Harry Rawlings (Liam Neeson), a master thief who, along with his confederates Gunner (Jon Bernthal) and Perelli (Manuel Garcia-Rulfo), is plotting a big score worth a couple of million dollars. It goes south, however, and their van explodes in a hail of gunfire with police, apparently killing the three men and destroying all the money. It leaves the three widows—Veronica Rawlings (Viola Davis), Linda Parelli (Michelle Rodriguez) and Alice Gunner (Elizabeth Debicki) not just without the cash to live on, but in imminent danger.

That’s because the stolen money belonged to Jamal, who needs it to fund his campaign. He threatens Veronica, ordering her to pay back the cash or else. She calls a meeting with Linda, who’s lost her store because of her husband’s gambling debts, and Alice, who’s being prodded by her mother (Jacki Weaver) to take up a career as a paid escort, and suggests that they pull off a heist Harry had meticulously planned in a notebook that was one of the few things he left her. It involves stealing a horde of cash from the Mulligan family mansion/campaign center—money Tom had accumulated over his years in office.

The three women agree to attempt the job, enlisting a fourth, Belle (Cynthia Erivo), a hairdresser who’s also Linda’s babysitter, to be their getaway driver, and pumping David (Lukas Hass), a real estate man who’s one of Alice’s clients, for information. Meanwhile Jatemme (Daniel Kaluuya), Jamals’ loose cannon brother and chief enforcer, takes action on his own, among other things targeting the Rawlings family chauffeur, Bash (Garret Dillahunt). Other characters fly in and out of the complicated plot, most notably Amanda (Carrie Coon), the widow of Coburn (Jimmy Nunn), yet another of Harry’s old gang, whom Veronica approaches for advice—only to find out something she might prefer not to know and her late husband.

With an implausible last-act twist that requires a bevy of flashbacks to explain, as well as a very busy heist scene as the women pull off the job at the Mulligan mansion and others intervene to foil it, “Widows” is convoluted, but in the end pretty simple. Based on misdirection from the very start, it winds up a flashy but essentially empty exercise, even though it clearly wants to say something about how badly women continue to be treated, especially by their spouses.

And yet it’s easy to go along for the bumpy ride, in spite of some muddled work by McQueen, because the cast is so strong. Davis delivers yet another powerhouse performance, and Rodriguez, Debicki and Erivo are not far behind. Predictably good supporting work comes from Farrell, Neeson, Henry, Haas and Duvall, and though Kaluuya overplays the gangsta villainy to the point that you’re just waiting for him to get a well-deserved comeuppance, they rest of the cast does what’s required of them expertly.

The technical work is topnotch as well, with both Adam Stockhausen’s production design and Sean Bobbitt’s cinematography first-rate, and though Joe Walker’s editing lacks complete clarity in some of the more complicated sequences, Hans Zimmer’s score is better than usual.

So “Widows” is a mixed bag, but one in which the positive elements slightly outweigh the negative ones. Very slightly, it should be emphasized.