Actor Cynthia Erivo tops the list of reasons the first part of a two-part film adaptation of the musical “Wicked” likely will extend the good fortune that has paved this story’s road from the beginning. It’s quite a zigzag lineage: From L. Frank Baum’s “Oz” adventures to MGM’s 1939 movie musical to Gregory Maguire’s increasingly raunchy quartet of “Wicked” bestsellers to the more acceptably edgy 2003 Broadway musical smasheroo. The movie is directed by Jon M. Chu in a style appropriate to the material. In other words, it’s filmed every which way. It accommodates a little camp, a lot of “Wizard of Oz” throwbacks and plenty of Easter eggs. “Wicked’s” insurrectionist spirit, animal-rights activism and larger anti-fascist allegory all inform the actions of two formidable female roles at the center. The witches-in-training are buoyed by duets and power ballads, courtesy of composer and lyricist Stephen Schwartz, no longer best known for “Godspell” since “Wicked” came along. Chu, who also made “Crazy Rich Asians,” “In the Heights” and the two standout “Step Up” dance movies, knows enough to get out of the way whenever Erivo takes over as Elphaba. Erivo is aces, as we’ve known for a while now. A huge talent in a time of triple-threat scarcity, she pours everything she has vocally and dramatically into getting this thing in the air, for at least some of its 161 minutes. The official title is “Wicked: Part I,” and it covers Act 1 of the two-act musical’s narrative. “Wicked: Part II” arrives on Nov. 21, 2025. Consider the entire five hours of Chu’s two-part “Wicked” as the bonus-materials screen edition of the show, with a 364-day intermission. Ariana Grande is good, too, as Glinda, the pampered entry-level witch and social clique bait of Shiz University, both repelled by and attracted to the intriguing magnetism and enviable sorcery of her green-toned roommate. The emotional bond between her and Elphaba, the latter having known only cruel ostracization her entire life, emerges from a place of mutual loathing, spiced with a hint or three of sexual attraction. (In the books, author Maguire is less coy about the multidirectional intimate lives of his characters.) What made the Broadway “Wicked” fly was pretty simple, in the end: A story about young women navigating a variety of social terrors and teaming up to combat a heartless patriarchy, with songs. The Elphaba-Glinda dynamic was always the glue holding the show together. The challenge comes in reconciling the material’s potentially irreconcilable internal differences. “Wicked” is a show trying to give everybody a great time while activating a story about a terrible time. It’s a dystopian tale hinging on a charlatan leader determined to hold onto power by putting his appointed scapegoats in cages (real goats, in some cases, among the talking animals under attack) while demonizing Elphaba, a powerful woman of color. And while “Wicked” may be timely some times more than others, it’s also a mite heavy-handed. Winnie Holzman wrote the stage version’s book and worked on the screenplay with Dana Fox (a co-writer on “Cruella”). Because they have plenty of time and only an act’s worth of structure to deal with, the writers pull a few strands from Maguire’s books; expand the interaction between Elphaba and her favored, not-green sister Nessarose (Marissa Bode), also attending Shiz; depict Elphaba’s tutoring sessions in some detail with Madame Morrible (Michelle Yeoh); and generally air out the pace of things. That’s a mixed blessing. The movie feels alternately hectic and languid, and while it’s fun to see Jeff Goldblum as the Wizard, he and Yeoh manage gravitas of differing varieties without much urgency. “Wicked” gets its design act together once Elphaba and Glinda board a nifty steampunk train to Oz; up until that point, director Chu often struggles for momentum. In the much-loved tune “Popular,” for example, there’s no real build to the staging, just a lot of extra beats for mild comic shtick. Elsewhere, Chu and his digital-effects army go nuts, turning Elphaba’s misbegotten spell on the Storm Trooper simian brigade into a protracted exercise in bloodless body-horror anguish. It was like that on stage, too, but shorter. I appreciate the degree to which production designer Nathan Crowley has built a lot of what we see on screen, from the mushroom huts of Munchkinland (with a touch of “The Wicker Man”) to the express train to Oz. But did the open-air Shiz University campus really need to look like a 1990s outdoor shopping mall somewhere in San Diego? Little of this will matter to the fan base unless they’re design majors. When Erivo and, at her best, Grande grab hold of their showcase numbers, all is well, or well enough. But a film musical’s visual language and blending of tones has a direct relationship to the quality of the result. How could it be otherwise? Yet it’s a fact — a stage-to-screen adaptation’s actual quality has nothing to do with its popularity. Take “Les Miserables,” a comparably sized musical phenom on stage, turned into a hugely successful film in 2012. Aesthetically “Les Miz” and “Wicked” have little in common, since “Les Miz” was filmed halfway up the nostrils of its leading characters, for gritty realism, while Chu’s “Wicked” sticks as it must (to quote a lyric from the 1971 “Willy Wonka and the Chocolate Factory”) to pure imagination. Too often, though, the magic in “Wicked” remains stubbornly unmagical. And whenever Erivo isn’t around to make us believe, and take the mechanics of “Wicked” to heart, “Part I” reveals what’s behind the curtain: an adequate set-up for next November’s second act. “Wicked: Part I” — 2 stars (out of 4) MPA rating: PG (for some scary action, thematic material and brief suggestive material) Running time: 2:41 How to watch: Premieres in theaters Nov. 21 Michael Phillips is a Tribune critic.