“You can’t keep doing this forever.” – Diana Prince/Wonder Woman to a bruised and battered Bruce Wayne/Batman.

“I can barely do it now.” – Bruce Wayne/Batman.

Boy, they sure do have a lot of coveted orbs and ancient cubes and magical stones in the superhero universes.

Often these glowing objects have been tucked away for millenniums, lest they fall into the wrong clutches of the obligatory fire-eyed entity that talks with a deep, mechanical voice and rages on about destroying all the planets, because that’s what those guys aspire to do.

In “Justice League,” the MacGuffins are known as Mother Boxes, and there are three of them: one hidden in the deepest depths of the sea; one under heavy guard on Themyscira aka Paradise Island aka the home of the Amazons, and one buried by man. By the looks of it, man did the worst job of hiding a Mother Box, seeing as how a couple of old-timey Viking types apparently dug a six-foot hole and covered the Box with dirt.

We need a reason for Bruce Wayne/Batman (Ben Affleck) to recruit a new team of warriors, and the reason is a giant, evil creature named Steppenwolf (a not particularly memorable CGI villain voiced by the great Ciaran Hinds) has come to Earth to retrieve the Mother Boxes and impress his own mommy and, oh yes, destroy all worlds as we know them.

Doesn’t take much imagination to know how it’s all going to turn out — but the fun in “Justice League” is in seeing Affleck’s Batman and Gal Gadot’s Wonder Woman teaming up with Ezra Miller’s Barry Allen/Flash, Jason Momoa’s Arthur Curry/Aquaman and Ray Fisher’s Victor Stone/Cyborg.

It’s a putting-the-band-together origins movie, executed with great fun and energy.

About those actors playing the Fab Five (with room for more to come). They’re a wonderful (and ridiculously good-looking) group of performers, and they play well together. Thanks to a nifty screenplay by Chris Terrio and Joss Whedon and just the right mix of “heavy-iosity” and humor in the directorial tone of Zack Snyder, “Justice League” marks a solid step forward for the DC Comics Extended Universe.

“Justice League” opens in the immediate aftermath of the death of Superman. Early on, we hear Norwegian pop star Sigrid singing Leonard Cohen’s “Everybody Knows” and we see fear and violence and uncertainty on the streets of Gotham and Metropolis. (At times it’s a bit confusing as to which city we’re visiting. Remember, in this particular universe, Metropolis looks a lot like Chicago with layers of CGI skyline, and Gotham City is just across the bay.)

With the help of his ever-loyal butler/strategist Alfred (Jeremy Irons), Bruce Wayne recognizes a pattern of destruction at various points on Earth (creepy robotic flying insect creatures are the key), leading him to realize the planet will soon be attacked. By the time he makes contact with Diana Prince, she says the attack isn’t coming — it’s already here. Steppenwolf has invaded Paradise Island and has stolen one of the Mother Boxes.

Jason Momoa brings a biker/rock star swagger to the role of Aquaman, who initially finds Bruce Wayne amusing (“You actually dress up as a bat?”) and is hesitant to join the battle until his own underwater people are attacked. Ray Fisher’s Cyborg, still learning by the minute about his powers, is another reluctant warrior who eventually joins the team.

There’s no such hesitation on the part of Ezra Miller’s The Flash. He says “YES!” to Bruce Wayne’s pitch before Wayne can explain what the job entails. (Like Tom Holland’s Spider-Man in the “Avengers” universe, Miller in essence represents every teenage comic-book geek. Sure, they have their own impressive skill sets — but they’re fans of the big boys and girls, and they’re giddy about the prospect of joining the team.)

It’s maybe the least spoiler-y spoiler in modern movie history to “reveal” Henry Cavill’s Clark Kent/Superman makes a return in “Justice League.” I’ll not reveal the circumstances, but I will say The Flash spoke for me when he voiced concerns about the possibility of a Stephen King “Pet Sematary” scenario.

As terrific as the primary actors are in playing the superheroes and their alter egos, “Justice League” also benefits from an amazing roster of great veterans in smaller roles, from the aforementioned Hinds and Irons to Amy Adams as Lois Lane; Joe Morton as Dr. Silas Stone; Connie Nielsen as Queen Hippolyta; Billy Crudup as Barry Allen’s dad; Diane Lane as Martha Kent, and J.K. Simmons as Commissioner Gordon.

Love that J.K. Simmons, but it was a little jarring to see him beaming the Bat Signal into the skies above Gotham, ’cause I still remember him playing that editor from the Daily Bugle who was convinced Spider-Man was a menace to society.

The most likable warrior, the coolest warrior, the most magnetic warrior in “Justice League” is …

Wonder Woman. In rapid fashion, Gal Gadot’s WW has become my second-favorite superhero in all the comic book universes, second only to Robert Downey Jr.’s Tony Stark/Iron Man.

And rapidly gaining.

★★★1⁄2

Warner Bros. Pictures presents a film directed by Zack Snyder and written by Chris Terrio. Rated PG-13 (for sequences of sci-fi violence and action). Running time: 119 minutes. Opens Friday at local theaters.