“Justice League,” the DC Comics superhero movie reaching theaters Friday, Nov. 17, is less about justice, per se, than about self-sacrifice, teamwork and finding a way to go on in the face of death. And not just the death of Superman, who purportedly perished in last year’s “Batman v Superman: Dawn of Justice,” but that of a 20-year-old college student named Autumn Snyder — a daughter of director and co-writer Zack Snyder.

After her passing in March, Snyder threw himself back into work in what he later called “a cathartic thing . . . to just bury myself and see if that was the way through it.” It wasn’t. After two months, he withdrew and asked filmmaker Joss Whedon — whom he’d already had helping rewrite some scenes in this all-star story of Batman (Ben Affleck), Wonder Woman (Gal Gadot), Aquaman (Jason Momoa), the Flash (Ezra Miller) and Cyborg (Ray Fisher) defending Earth against alien warlord Steppenwolf (Ciarán Hinds) — to direct the final reshoots and bring the movie home.

“Zack made the effort to call everyone specifically,” Fisher recalls. “It was terrible news to get, but Zack said that he was having to step away, understandably so, to deal with family issues. I can’t imagine how tough it was for him.” When shooting resumed, Fisher said, the set felt “just different. But it was very much that sense of let’s get it done, let’s get it done for Zack, let’s get it done for the fans, let’s get it done for the people who need and want this film.”

“I heard about it fairly soon after the event,” Charles Roven, a producer of DC’s films going back to “Batman Begins” (2005), says gingerly. “It was absolutely devastating emotionally. And in true Zack and Debbie style,” he says, referring to fellow producer Deborah Snyder, Zack’s wife and Autumn’s stepmother, “they took the time to grieve and then went back to stay the course.” When they no longer could, “Everybody completely understood.” With Whedon — who wrote and directed Marvel’s two Avengers movies before decamping to DC to develop a Batgirl film — already working on “Justice League,” he was, says Roven, “the natural individual to go to, to see if he were willing to step in and finish the movie.”

Whedon “actually wrote us all a really nice letter,” Fisher says, “introducing himself and just giving us the tidbits that he was thinking of and explaining the situation for all of us.”

His arrival led many to wonder if Whedon’s trademark wit and humanism would lighten what Variety has called “DC’s house style of grim darkness.” Roven and Affleck have acknowledged that reviews of “Man of Steel” (2013) and “Batman v Superman” often described those hit films as dark and dour, and when director Patty Jenkins’ “Wonder Woman” this year pleased audiences and critics alike with its more positive and hopeful storytelling, Whedon’s late stewardship of “Justice League” suggested the film might go more in that direction.

“I really don’t know how to break down the scenes that [Joss] wrote with Zack versus the scenes that he wrote later,” Roven says. “If you take ‘Man of Steel,’ ‘Batman v Superman’ and ‘Justice League’ as a trilogy — they were all directed by Zack, with the third one having some influence by Joss — I would say this is the lightest of the three. That doesn’t mean it’s a comedy!” Trust us — nobody will think that.

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Industry estimates project a $110 million to $120 million domestic opening weekend, comparable to the $121 million made by Marvel’s “Thor: Ragnarok” when it arrived earlier this month. But for Roven — who was age 10 when the Justice League of America debuted with a slightly different lineup in “The Brave and the Bold” #28 (cover-dated March 1960, on sale Dec. 29, 1959) — the movie actually seems to be about more than the millions it will make. The millions are important, obviously, but the longtime Hollywood heavyweight — who in an interview has been cordial but controlled, sharing a chuckle occasionally but instinctively watchful of words — appears to let his guard down when his mind goes back to those Silver Age days.

“Oh, yeah!” he says, suddenly lighting up. As a kid in those much more casual times, “I’d go to the neighborhood liquor store and buy ‘Action Comics’ and ‘Detective Comics,’ and when I read my first Justice League comic I was completely flipped out and thrilled!”

If “Justice League” makes audiences flipped out and thrilled, it will have done its job.