WHAT IT’S ABOUT A year after slapping Alicia Florrick (Julianna Margulies) for betraying her on the series finale of “The Good Wife,” Diane Lockhart (Christine Baranski) has decided to move on, but a college friend who invested her money loses everything when his Ponzi scheme collapses. Diane had landed a job at Lockhart & Lee for the daughter of this old friend — one Maia Rindell (Rose Leslie) — who is promptly fired when the scandal breaks. Now, both Maia and Diane need a helping hand, and one is extended by Robert Boseman (Delroy Lindo) who, with Lucca Quinn (Cush Jumbo) and Barbara Kolstad (Erica Tazel), runs a law firm that takes on clients in need, notably some who have been brutalized by the cops. This spinoff was created by “Wife” showrunners Michelle and Robert King.

MY SAY “The Good Wife” was essentially the story of a journey, notably Alicia’s, and with “The Good Fight,” Diane finally gets a ticket to ride. We see her after that infamous hallway slap scene, watching the inauguration of Donald Trump in a darkened room. She abruptly turns off the set, then books the next flight to France. Apparently Canada is either too close or too cold for her taste. What happens next literally spins her around. Betrayed by a college friend, and nearly broke, she’ll have to remain in Trump’s America after all.

Poor Diane. That castle in Provence did look so inviting.

Because viewers have so much shared history with Diane, pity is not the first emotion most will feel, nor should. She’s a pragmatist, foremost, also coolly calculating. We know she’s an idealist, but only when convenient. She runs for the exit when Trump becomes president, runs back when the money gets tight. Most viewers admired Diane, but they didn’t exactly love her. This opener reminds them why.

A great and essential character on “The Good Wife,” Diane is also the last one you’d expect to get top billing in the spinoff. Some “Wife” fans in fact had hoped Carrie Preston’s Elsbeth Tascioni or maybe Martha Plimpton’s Patti Nyholm would get an extended, and deserved, close-up here. They had quirks, and style. They were also approachable human beings. Consider their absence, at least in this first season, a keen disappointment.

The Kings may have also sized up Diane’s shortcomings, so that’s where Lucca and Maia come in. Lucca was a fan favorite, and they’ll be pleased with her here — especially when she belts out an expletive to some creep who’s bullying Maia over his lost fortune. (Expletives will be heard only in the All Access version.)

That leaves Maia. Leslie plays her as a naif, a lamb among wolves. She’s also a gay woman who’s faced down bigotry, but — like Alicia, and now Diane — she’s at the outset of a journey. At the new law firm, she’ll fight the good fight with Lucca, and in the process, maybe even teach Diane there’s more to life than just billable hours.

What’s missing? The better question is “who?” “Fight” has three solid supporting leads, two fine newcomers — Tazel (“Justified”) and veteran Lindo — and a few welcome curtain calls, like Denis O’Hare, back as a judge, and Sarah Steele, who reprises feisty, pushy legal clerk Marissa Gold.

In fact, what’s missing is a strong central character, or someone to care about, or worry about, or love and occasionally loathe, and especially someone with a complex inner life, and uncertain moral bearings. What’s missing is someone who grabs and holds our attention and thereby forces us to pay five bucks a month to CBS All Access to find out what happens to her next.

Alicia’s missing but — sorry — her story is done.

BOTTOM LINE Solid opener, compelling premise, good cast and one major hole.