In a captivating opening, Princess Irulan (Virginia Madsen) narrates the history of a universe once governed by machine titans and the humans' journey to reclaim their lost knowledge. To counter their past apathy, two distinct training programs focused on mathematics and psychic abilities emerge, leading to the rise of the powerful spice melange. This rare substance not only extends life but also amplifies certain psychic powers, essential for the Galactic Spacing Guild's navigators to "fold space" for swift interstellar travel. The one and only source of this invaluable spice is the arid desert planet of Arrakis, affectionately known as Dune. The native Fremen, a nomadic tribe, hold a legend of a messiah destined to come from another world.
In the year 10,191, a representative of the Guild visits Kaitain to address the emperor Shaddam IV (José Ferrer) about the escalating threats to spice production. The emperor reveals his treacherous plans to eliminate the noble Atreides house due to its rising popularity and purported secret army armed with weirding modules, which pose a significant threat to his rule. Hence, he intends to assign the Atreides the difficult task of mining spice on Arrakis, only to ambush them later with the Harkonnens, their merciless rivals. The emperor's henchman commands that Paul Atreides (Kyle MacLachlan), the duke's son who possesses prophetic dreams about his crucial role, must be silenced. This draws the attention of the Bene Gesserit sisterhood, particularly Gaius Helen Mohiam ([Siân Phillips]), who plans to meet the young man, as he is a product of their long-established breeding initiative aiming to produce the superhuman Kwisatz Haderach.
On the sea-laden world of Caladan, home to House Atreides, Paul grapples with the inexplicable notion of why the Harkonnens would willingly cede their power in Arrakis. Despite his confusion, he understands their family must embrace this new challenge. Thufir Hawat (Freddie Jones), a skilled mentat, informs Paul that their move to Arrakis is motivated by the promise of a new army. Meanwhile, Gurney Halleck ([Patrick Stewart]), Paul’s mentor, pushes him through rigorous training, honing his combat skills in preparation for the trials of manhood. Paul successfully utilizes a weirding module against a combat robot, showcasing his remarkable talent.
As the Bene Gesserit test Paul, with his mother Lady Jessica (Francesca Annis) prayerfully anxious for his safety, he endures a grueling examination that involves a deadly gom jabbar. To Paul’s disbelief, the test features the dangerous Water of Life, a substance derived from the bile of massive Arrakis worms, which no male has ever survived consuming. Under immense duress, facing excruciating pain while forcing his hand into a box, Paul triumphs against all odds, astonishing the reverend mother.
Meanwhile, on Giedi Prime, the grim home of House Harkonnen, the grotesquely deformed Baron Vladimir Harkonnen ([Kenneth McMillan]) schemes sinister revenge against the Atreides, enlisting his toxic nephews, Glossu Rabban ([Paul L. Smith]) and Feyd-Rautha ([Sting]), to eliminate the duke once the Atreides assume Arrakis' control.
Upon reaching Arrakis, Duke Leto receives crucial insights from his aide Duncan Idaho (Richard Jordan) regarding the underestimated Fremen, whose immense numbers could be potential allies. As Paul and Leto engage with Dr. Kynes ([Max von Sydow]), a spice mining leader, they witness a terrifying sandworm attack during a spice extraction operation. Demonstrating noble leadership, Duke Leto prioritizes worker safety over spice extraction, cultivating the trust of Dr. Kynes.
However, the Harkonnens launch a fierce assault on the Atreides, capitalizing on the emperor's elite army, the feared Sardaukar, along with an insider traitor: Dr. Wellington Yueh ([Dean Stockwell]). As Leto attempts a doomed assassination against the Baron equipped with a deadly tooth capsule, he suffers catastrophic defeat and loses his life during the conflict. Paul and Jessica barely escape to the vast desert, surprisingly expecting their child amid dire circumstances.
In the desert, they join forces with the Fremen, led by Stilgar ([Everett McGill]), as Paul assumes the name Muad'Dib. The Fremen, suspicious yet hopeful, believe he may be their prophesied leader. As he trains the Fremen in new combat techniques, Paul begins to destroy spice production, thus threatening the galaxy's economy. Meanwhile, Jessica, in perilous transformation, consumes the Water of Life, resulting in a violent reaction and a premature birth of their daughter Alia ([Alicia Witt]), who possesses extraordinary powers.
With the Fremen rallying behind Paul, they launch relentless attacks to halt spice production, drawing the attention of the Spacing Guild and placing the emperor on high alert. A fateful reunion with Gurney, now a smuggler, leads him to join forces with Paul. As Paul deeply bonds with Chani ([Sean Young]), the daughter of Dr. Kynes, he resolves to drink the Water of Life, surrendering to fate.
Paul enters a transformative state in the desert that ignites new abilities: he can now tame the sandworms of Arrakis, uncovering hidden water caches that could eradicate spice forever. With newfound precognition abilities, he envisions an impending invasion fleet commanded by the emperor, galvanizing his Fremen army for a counterattack.
When the emperor arrives, chaos ensues as he executes Rabban for his failures. As the tension mounts between the remaining Harkonnens and Paul, a formidable battle unfolds. Paul leads a fierce assault using the desert's daunting storms to amplify their attack. In the ensuing carnage, he confronts and defeats Feyd in an excruciating duel, effectively claiming his destiny. With the empire’s power stripped and a new era dawning, rain begins to pour on Arrakis, breaking centuries of drought. Alia’s triumphant words echo, "And how can this be? For he is the Kwisatz Haderach!"
