Having turned a sci-fi B-movie into a groundbreaking blockbuster saga, then watched as other filmmakers gradually wore out the series' welcome, James Cameron wants to set things right with Terminator: Dark Fate. Returning as producer and one of five men writing the story for this woman-centric installment, he envisions the Tim Miller-directed film as the only real sequel to 1991's Terminator 2: Judgment Day. Everything else, according to Cameron, takes place in some alternate reality — maybe the same universe where millions are clamoring for four Avatar sequels.

Dark Fate does offer a fair bit of pleasure to those wanting a 21st century retread of T2. But it suffers greatly from obeying the imperative the first sequel established: Trying to blow minds and up the ante the way that FX-pioneering adventure did, this one offers a series of action set pieces that go from big to huge to ludicrous, even as the script's additions to fear-the-future mythology underwhelm. Aside from predictably excellent CGI, an underutilized Mackenzie Davis is the film's best new addition; Gabriel Luna is also strong, a more than capable heir to Robert Patrick's T-1000, delivering the same laser-focused menace while adding some people skills to the mix.

The film begins with some VHS clips from that episode, during T2, when Sarah Connor (Linda Hamilton) was hospitalized for her presumed delusions — ranting doom and gloom about the AI-dominated future while psychologists snickered. Presumably, the filmmakers chose specific clips to establish this story's themes, but I can't tell you what Sarah has to say: At the New York City press preview, the sound was off during the movie's beginning, and nobody cared enough to restart the pic once it came on.

We soon find ourselves in Guatemala in 1998, where Connor and her son John (Edward Furlong) are enjoying having stopped the evil Skynet AI before it got going. Out of nowhere comes a version of Arnold Schwarzenegger's T-800 robot that is clearly not the one that just helped them save the world. 

Twenty-two years later, two new visitors arrive in Mexico City, hailing from a different version of the future than the one the Connors fought to prevent. Both visitors emerge naked from blue spheres that crackle with electricity, as in earlier films. But both spheres emerge far above ground level, leaving the time-travelers to endure punishing falls. Clearly, the people at the controls need to work on their aim.

We expect some fan service when the first time-traveler convinces strangers to give her their clothes, or when she shows up to rescue an unsuspecting woman from certain death; but the screenplay self-consciously avoids lines we know by heart. Before you give it credit for not pandering, be assured that the catchphrases will return soon enough, and that their delivery will elicit as many winces as grins.

Grace (Davis) turns out not to be a Terminator, anyway. She's an "augmented human," with super-strength and six-million-dollar senses. She was sent back in time to rescue an auto factory worker named Dani (Natalia Reyes) from the latest robo-assassin, a T-1000 update known as Rev-9 (Luna). This mean machine kills Dani's family while tracking her down, then wreaks havoc in her workplace, and the film's effects teams have had a blast designing him: Like the bad guy in T2, he's a nigh-indestructible shapeshifter whose liquid-metal body repairs every wound. But anybody lucky enough to slow him down will see that he can split his body in two, with the humanoid form leaving its carbon-black skeleton behind and both 'bots battling independently. When a fight is over, the skeleton reenters its skin like a spa visitor dipping into a hot tub.

Grace isn't so lucky. Intense expenditures of energy leave her near death, needing a cocktail of pharmaceuticals to recharge. Good thing a human being shows up to save the savior: Weathered and fierce, Sarah Connor has spent decades preparing for this moment. She collects Grace and Dani, and immediately starts arguing with the cyborg about how to protect the young human. Grace, knowing Rev-9's power, wants to flee and hide; Sarah, whose dialogue leans toward pronouncements like "I'm gonna kill that motherfucker," wants to use Dani as bait.

Telling Dani she knows what it's like to learn you're the MVP womb of the future, Sarah makes pronouncements that clearly rub Grace the wrong way. But the two keep Dani safe until she can find her own footing. The women start moving north, toward a spot near Laredo whose coordinates they've been given mysteriously. The audience knows who they'll find there, but they may not understand how Mr. "I'll Be Back," the android assassin now passing himself off as a human named Carl, has become an old man.

It seems unlikely that anyone back in 1984 would have expected that cybernetic Terminators would not only bleed when wounded, but age alongside the humans they were sent to infiltrate. If that unlikely fact was explained somewhere along the way in this franchise, certainly none of this episode's screenwriters expect us to want a refresher. They also don't expect us to wonder what rules might constrain the Rev-9's body-splitting trick.

Instead, the filmmakers focus on action: highly enjoyable chase scenes before the women team up with T-800, increasingly goofy ones after that. Recall that in T2, resistance fighters in the future captured a T-800 and reprogrammed it to serve their side. Here, the robot does the reprogramming itself, learning empathy for weaker beings in that place so short on empathy, the U.S./Mexico border.

One might expect that, having hired Deadpool director Miller, the filmmakers have a sense of irony about all this and wanted him to bring some meta-movie wit to the action. No such luck. This film contains even less humor than the last one, and is instead focused on making Carl a martyr; in scene after scene, it foreshadows his willingness to die for the humans he once hunted.

We're distracted from the staleness of this storyline by sequences that strain awfully hard to dazzle us. One long fight in the back of a falling cargo plane has combatants zipping to and fro in freefall; the next tosses them over a dam in a Humvee, sinks them and sets robot against robot on the bottom of a lake. By the time the movie's ready to kill its latest-greatest villain, fans have gotten a fine lesson in the perils of sequel-making one-upmanship.

Worrisomely, our heroes drive off with the explicit promise to prepare for future battles. Will some other storyteller arrive to rescue the franchise and its self-appointed saviors from themselves?

Production companies: Lightstorm Entertainment, Skydance
Distributors: Paramount, Twentieth Century Fox
Cast: Linda Hamilton, Arnold Schwarzenegger, Mackenzie Davis, Natalia Reyes, Gabriel Luna, Diego Boneta
Director: Tim Miller
Screenwriters: David Goyer, Justin Rhodes, Billy Ray
Producers: James Cameron, David Ellison
Executive producers: Dana Goldberg, Don Granger, Edward Cheng, John J. Kelly, Tim Miller, Bonnie Curtis, Julie Lynn
Director of photography: Ken Seng
Production designer: Sonja Klaus
Costume designer: Ngila Dickson
Editor: Julian Clarke
Composer: Junkie XL
Casting directors: Mindy Marin, Lucinda Syson

Rated R, 128 minutes