You can’t envy Francis Ford Coppola for the inevitable scrutiny of the spotlight after his hiatus of seven years and his vaunted place in film history. As a leading light of the New Hollywood in the 1970s, Mr. Coppola created in “The Godfather” not just an endlessly watchable modern classic, but a cultural touchstone, a part of America’s vocabulary for family, business, and machismo. His follow-up,1974’s “The Conversation,” confirmed that he could make a masterpiece with very different material and themes, while 1980’s “Apocalypse Now” yielded the kind of iconic scenes and sensations that moviegoers long for today.

All this well-rehearsed mythology and mastery became burdensome years ago, and the epic struggles that followed “Apocalypse Now” — to name just one, the ill-conceived and ill-received “One From the Heart” — have since attenuated into a career of second tries and second-guessed average works. At the risk of oversimplifying, Mr. Coppola’s unironically grand moviemaking can arouse cynicism more easily than, say, the latest kinetic spectacles and mercurial characters of another old master such as Martin Scorsese (or the valedictory roundelays of the late Robert Altman).

“Youth Without Youth,” Mr. Coppola’s gnomically titled return, bears the heartfelt, personal stamp of a director who has metaphorically staged the drama of his filmmaking saga before in “Tucker: The Man and His Dream” and even in “The Godfather: Part III.” A self-consciously ambitious riddle of love, regret, and cursed metaphysics, “Youth Without Youth” implicitly acknowledges Mr. Coppola’s anxieties as a great director, but, sadly, fulfills many of them with a murky folly of genre-blurring, scattered epiphanies, and wordy philosophizing that might sound better in French.

Electrified by a lightning bolt on the way to possibly committing suicide, blocked Romanian academic Dominic Matei (Tim Roth) is suddenly and magically endowed with superhuman genius and a reversal of the aging process. He recuperates and regenerates under the wondering, studious eyes of Professor Stanciulescu (Bruno Ganz), but, this being 1938, his extraordinary case attracts the attention of the Nazis (now as ever in the movies, diabolically drawn to the cutting-edge).

Beyond this first portion, which groans under exposition, the movie gets a little too funky for any streamlined summary. Once recovered, Dominic has an affair with an admirer (Alexandra Pirici) who turns out to be an agent for the Third Reich, but he’s also experiencing periodic apparitions taking the form of his devil’s advocate double — a regrettable device that’s only slightly more natural than John Lithgow’s camp doppelganger in “Raising Cain.”

Dominic tries to elude interested parties in Switzerland and meets a tourist, Veronica (Alexandra Maria Lara), who, after also getting zapped by lightning, believes she’s the disciple of a seventh-century Indian scholar. She communicates in Sanskrit, and Dominic, still toiling under the dream of completing a great work of scholarship, sees the chance to pull up the roots of human language all the way to its source. Their interactions yield some of the film’s most overwrought scenes, and the tussle with big-idea speculations suggests that Mr. Coppola’s abandoned sci-fi epic, “Megalopolis,” might have been a fortunate near miss unless mounted mostly as spectacle.

Dominic’s story in “Youth Without Youth” shifts as freely among memories and realities as does the film’s 1978 source, a novella by the Romanian religion scholar Mircea Eliade (who wrote, most notably, “The Sacred and the Profane”). But what were ludic puzzles of mind and self in the book become clammily romantic and sometimes ridiculous in Mr. Coppola’s vision, demonstrating the dangers of visualizing the intellectual conceits of a text. At times one recalls, longs for, and understands the astringency that Alain Resnais brought to his kaleidoscopes of time and desire in the 1960s; the director’s playful, temporally fractured 1968 drama “Je t’Aime, Je t’Aime” also, oddly enough, featured a hero evading suicide.

As Dominic, Mr. Roth, bowed under that old baldness-extending age makeup and tweedy old-world suits, is unable to anchor the film. While any actor would likely find the movie’s verbose backstory and metaphysical urgency hard to bring home, Mr. Roth’s lack of depth will fuel skeptics who might call him more of a personality than an actor, one who excels elsewhere as a belligerent sputterer-seether, like a British Buscemi. One can imagine the against-type thinking that sought to tap Mr. Roth’s angry-young-man pith as the implied core of this revivified, reflecting gentleman, but the actor makes little impression at the center of the movie’s maelstrom.

Among the supporting cast, Mr. Ganz is inconsequential and Ms. Lara, who also plays a past lover who makes Dominic remember Veronica, is similarly overwhelmed, though her youthfully noble face is arresting. Her diffident, wide-eyed appearance seems to lend itself to sliding into period dramas, whether in Hitler’s bunker (as his secretary in “Downfall”) or Manchester’s post-punk scene (as Ian Curtis’s mistress in “Control”).

Even if “Youth Without Youth” never comes off, its deep-dish, ersatz-European reverie of what-might-have-been versus what-could-be is often affecting in its unfashionable datedness. There may be flashes of the laughable, but there are also the lovely tableaux effortlessly orchestrated by a comfortable Mr. Coppola, even something as minor as the opening frisson of Dominic’s electrocuted umbrella flaming into a glowing skeleton. Though this original movie brat may be upstaged this season by his era’s proud descendant, Paul Thomas Anderson, noone should begrudge him another chance at bat for lower stakes.