If you’ve already lost the plot, worry not: With “Dune: Part Two,” filmmaker Denis Villeneuve does a smooth job of bringing the audience back up to speed, even if some viewers will have to remind themselves of the difference between a T-probe and a crysknife. Those who need no refreshing will want to hasten to their nearest multiplex to plunge once again into novelist Frank Herbert’s wildly imaginative universe, brought to expansive, very sandy life by Villeneuve. If it all leaves you colder than a dying ice planet, “Dune’s” thundering insistence on its own importance might begin wearing thin after the first two hours — at which point, cheer up! You only have 46 minutes to go!

As he did in “Dune: Part One,” Villeneuve brings passion and detail to a project steeped in cinematic legend and lore. Alejandro Jodorowsky’s abandoned 1970s “Dune” film remains a tantalizing what-if; David Lynch’s 1984 adaptation of Herbert’s sci-fi epic was an ambitious but largely dismissed good try. It didn’t help that George Lucas seemed to lift much of the book’s plot and overall vibe to create “Star Wars,” slathering it with generous dollops of nostalgia and playful humor. Villeneuve’s “Dune” movies deserve admiration if only for their fealty and ambition; the filmmaker’s respect for Herbert’s source material radiates from every frame of movies that feel as massive as they are minutely orchestrated.

What’s more, he has done a brilliant job of casting: Chalamet is the perfect actor to play a character who begins as something of a callow princeling, only to morph into someone more charismatic and sinister; Zendaya, mostly grim-faced, still exudes convincing moments of tenderness while teaching the tender-footed Paul the ropes of mercenary warfare and survival on Arrakis. There’s a lot of fancy desert-walking and sandworm-riding in “Dune: Part Two,” as well as a fair amount of blue-eyed glaring; while Ferguson’s Jessica goes off the deep end when it comes to Paul’s messianic future (donning some spectacular costumes and makeup in her role as a newly minted Reverend Mother), Javier Bardem provides the movie’s only genuine laughs in his warm and funny portrayal of Fremen leader Stilgar, whose insistence that Paul is The One borders on “Life of Brian”-esque goofiness.

Newcomers to the cast are all first-rate: Florence Pugh and Christopher Walken slip easily into their roles as Princess Irulan and her father, the Emperor Shaddam IV, and Austin Butler thoroughly banishes Elvis — at least for now — in his bald, blank-eyed portrayal of the psychotic Feyd-Rautha, whose gladiatorial exhibitions for his uncle Vladimir Harkonnen (Stellan Skarsgard, returning in all his prodigiously padded glory) are staged with fascistic precision.

Heavy with biblical themes of prophecy, sacrifice, redemption and resurrection — with Shakespearean grace notes of fate, family and revenge — “Dune: Part Two” manages to be busy and oddly inert at the same time. Things happen for sure in a plot wherein Paul must decide whether he’s an all-in revolutionary or a reluctant demigod; Villeneuve stages the requisite number of fights and battle scenes, which grow ever more incendiary with each confrontation. The audience is treated (subjected?) to more shots of a baby in utero than might be entirely comfortable, all in service to a subplot involving the sister who will presumably be joining Paul in the next chapter. It’s all meticulously conceived and impressively staged, but becomes repetitive and monotonous, devolving for anyone not completely steeped in the “Dune” universe into a hazy orange-and-ocher soup of dust, smoke, flames and sand.

So much sand. Like its predecessor, “Dune: Part Two” builds a world that’s undeniably spectacular, compressing a sprawling, borderline incomprehensible story into an efficient narrative-delivery system (Villeneuve’s perfunctory editing style takes getting used to, but it keeps things moving apace). For “Dune” fans, it gives them the majestic treatment their beloved novels have long deserved; everyone else might need to fight their way through the fog of canonical arcana and the Arrakis elements to find a grain of escapist pleasure. It’s in there somewhere, even if we have to wait for “Part Three.”

PG-13. At area theaters. Contains sequences of strong violence, some suggestive material and brief strong profanity. 166 minutes.