From the opening seconds of “Parthenope,” there’s no doubt that this is a Paolo Sorrentino movie. The Italian director’s films are characterized by outlandish imagery, an intoxicating cocktail of beauty and strangeness.

Shrouded by fog, we see an ornate coach — shipped from Versailles, as we’re about learn — sitting on a dock by the Bay of Naples. As if in a dream, the mists part to reveal an expansive, portly man, with white hair and a white suit, known only as the Commander (Alfonso Santagata). Like something out of “Cinderella,” this carriage is the Commander’s gift to the unborn title character (Celeste Dalla Porta), his goddaughter who will grow up to become a stunner, desired by men and women alike, and to sleep in this carriage turned canopy bed, a kind of gilded cage. Freedom seems to be a theme here, but the message is as murky as the fog.

And so begins this fractured fairy tale, an obtuse Neapolitan allegory loosely inspired by the myth of Parthenope, a siren whose name was originally given by the Greeks to the city that became Naples. Not coincidentally, it’s also where Sorrentino grew up.

But if “Parthenope” is a love letter to his hometown and its subject an embodiment of the city’s idiosyncrasies and contradictions — beauty and decay, religion and hypocrisy — the whole thing comes across like a deranged mash note, more off-putting than seductive.

Beginning with Parthenope’s birth in 1950 — in the waters of the bay itself — and stretching to 2023, when the septuagenarian (played, briefly, by Stefania Sandrelli) is retiring from an academic career, “Parthenope” is as tedious to synopsize as it is confounding to fathom. As a teenage college student of anthropology, she’s a whip-smart observer of human behavior.

Her field of study, defined by one character as the science of seeing, positions her as someone outside of life, rather than in it, an alien visitor unrestricted by terrestrial norms.

During a sojourn to the isle of Capri, for example, she enters into a love triangle with boyfriend Sandrino (Dario Aita) and her own older brother, Raimondo (Daniele Rienzo), who is shown in one scene sniffing his sister’s still-damp string bikini after she has shed it.

Other suitors include the novelist John Cheever (Gary Oldman) and a wealthy playboy who courts Parthenope from a hovering helicopter, like a bee waiting to pollinate a flower.

Nearly every conversation has a smoldering cigarette in it, including one in which Raimondo submerges himself in the ocean, only to surface, improbably, with a sodden butt still hanging limply from his gorgeous lips. Many of the shots in this section play like perfume ads, as other reviewers have noted.

But Raimondo’s story doesn’t have a happy ending, and as the film moves into the 1970s, we catch a glimpse of Naples during the cholera outbreak of that time. You wouldn’t necessarily know what’s going on here — because Sorrentino never bothers to offer context — but a tanker truck suddenly appears in one shot with an array of spray hoses mounted to the roof like the legs of a giant insect. It’s full of disinfectant, but what purpose does the scene serve? A metaphor for rot beneath the city’s photogenic surface?

Another scene features Naples’s signature panaros, blue baskets raised and lowered from apartment windows to retrieve groceries and other deliveries. Shot at night and seemingly lit from within, the baskets are as luminous as paper lanterns. But if you’re not familiar with Neapolitan culture, you’d never know what function these otherworldly sequences serve, except to add atmosphere.

Other interludes are even more alienating: In one, a naked young bride and groom from rival clans in the Camorra, the Mafia-like crime syndicate from the area around Naples, are forced to copulate in front of an audience in a public ritual of interfamily unity. In another, Parthenope engages in a sexual encounter with a predatory Catholic bishop (Peppe Lanzetta) while researching a local miracle involving a glass ampoule said to contain the dried blood of the Catholic martyr San Gennaro. (That’s a real thing.) Ludicrously, she’s wearing a garment made of LED crucifixes that makes her look like a half-naked Cher, if Bob Mackie were trying to get the singer excommunicated.

It’s just another of Sorrentino’s many impressionistic vignettes about Naples — he loves it, he hates it — that don’t add up to much. When Parthenope is briefly considering a career as an actress, for instance, she meets a movie star (Isabella Ferrari) whose masked face has been disfigured by plastic surgery. Who knows why?

For sheer oddity for oddity’s sake, nothing tops the scene near the end when Parthenope encounters a character too obese to move, played by an actor who seems to have inherited Brendan Fraser’s fat suit from “The Whale.” He’s all water and salt, we’re told, like the sea. Another metaphor for Naples?

Sorrentino’s dialogue lurches from the aphoristic to the inscrutable without bringing the story into focus. “Beauty is like war,” Cheever tells our protagonist, enigmatically. “It opens doors.” Raimondo’s problem, another character opines unhelpfully, is that he confused “the irrelevant with the decisive.”

Confused is right. Arguably, some of Sorrentino’s points could have been lost in translation. Even so, it’s hard to imagine that any of this made more sense in the original Italian.