The first thing to greet the audience for “Omar,” the Pulitzer Prize-winning opera by Rhiannon Giddens and Michael Abels, is an enlarged projection of the real-life title character’s face. In a strikingly eloquent 1850 photograph, the 80-year-old enslaved African man conveys a lifetime’s worth of wisdom, suffering, sorrow and grace.

“What is his story?,” you think to yourself.

Unfortunately, the San Francisco Opera premiere of “Omar” on Sunday, Nov. 5, at the War Memorial Opera House, offered few answers. It’s full of visual delights and theatrical innovation, including a deft use of the entire house as a performance space. But at its heart, this nearly three-hour opera is dramaturgically blurry, musically uneven and laden with a libretto of picture-book banality. 

“Omar” takes on what could have been a subject of taut fascination and drains it of nearly all its focus and drive.

• The making of ‘Omar’: Rhiannon Giddens sets up a multifront musical whirlwind for Bay Area audiences

Everything about the piece seemed like a recipe for success, beginning with the remarkable source material itself. Omar ibn Said, an Islamic scholar from a wealthy family in modern-day Senegal, was captured and sold into slavery in the American South. He lived out his life there, writing on a variety of learned subjects and leaving behind an autobiographical essay that is the only known slave narrative in Arabic.

If anyone could be expected to turn this story into a crystalline theatrical narrative, it would be Giddens, the versatile artistic polymath who is steeped in the cultural lore of the African American experience. She wrote the libretto alone and composed the score with an assist from the versatile Abels, best known for his evocative soundtracks for the films of director Jordan Peele.

In practice, however, “Omar,” an Opera co-commission that had its world premiere last year at the Spoleto Festival in Charleston, S.C., limps unsteadily from scene to scene and from theme to theme without ever finding a coordinated line of attack on its subject matter.

Is it a contemplation of the horrors of American slavery? Sort of, but not in any consistent way. 

Is it a treatment of the power of religious faith, whether Muslim or Christian? Again, only every now and again.

“Omar” doesn’t even provide a biographical view of its ostensible subject, because the character — notwithstanding a potent, vocally resplendent performance by tenor Jamez McCorkle — never takes on a life aside from what we can see in that photograph.

He stands proud and erect, he professes his faith in Allah, and he communes with the spirit of his mother, killed during the original slaving raid in West Africa. But the music tells us little of the man.

Instead, “Omar” gives us vignettes from his life, some historical and some invented. We get a glimpse of the devout Muslim community from which he sprang. There are short chapters devoted to the Middle Passage and the slave market in Charleston, mostly through the eyes and experiences of minor characters.

Omar spends several months on the plantation of the ruthless landowner who buys him, then makes a run for a more humane situation in North Carolina. There he is bought by a relatively benign Christian master, Owen, who tries to convert him.

It’s hard to know what to do with some of the politics at work here. How do we reconcile the gruesome treatment of the slave trade with the repeated dialogue about the differences between “good masters” and “bad masters”?

The scene in which Owen’s slaves greet Omar with “Welcome, brother, to our happy home” plays like something out of a Florida high school curriculum. The insertion at this point of a “frolic,” a joyous group dance tracing the Black roots of square dancing, only underscores the sense of dislocation.

At its best, Giddens’ score offers a canny fusion of Islamic, African American and operatic tropes. The overture sets a brisk, rhythmically zesty tone — conductor John Kennedy gave this and other uptempo passages a vigorous swing — and there are surges of melodic arias studded throughout.

The most exquisite of these comes in the second act, when Julie, the enslaved woman who is Omar’s confidante and savior, is reminded by his kufi, the knitted cap he wears, of her own secretly Muslim father. The text is surreal, as Julie recalls the forced separation of her family with a nostalgic glow instead of the expected sense of trauma. But the melody, delivered in bright, arching tones by soprano Brittany Renee in a magnificent company debut, sells the moment.

Elsewhere, the score tends to bog down into a talky conversational pace and minor-key harmonies that don’t go anywhere.

If the text of the piece often flounders, the production — with vivid stage direction by Kaneza Schaal and a sumptuous design by Christopher Myers with set designer Amy Rubin and costume designers April M. Hickman and Micheline Russell-Brown — provides constant engagement. The use of Arabic script as a design element, underscoring Omar’s rare gift of literacy, is a lovely and telling choice.

Sunday’s performance also brought skilled contributions from mezzo-soprano Taylor Raven as Omar’s mother, bass-baritone Daniel Okulitch as the two plantation owners, and tenor Barry Banks in another double assignment as the slave auctioneer and Owen’s fellow Bible-thumper (an analog to Col. Pickering in “My Fair Lady”).

Tenor Edward Graves, a current Adler fellow with the company, delivered a gorgeous and all-too-brief solo as one of the prisoners in the Middle Passage slave ship whose sinuous phrasing seemed to stop time for a moment. The chorus of African American singers assembled for the occasion was never less than terrific.

In the end, though, “Omar” seemed to fade away even as we watched and listened. As it came to a close, the figures in his life, past and present, joined forces to exhort him: “Tell your story, Omar. You must, or they will never know.”

And the audience was left with the nagging and still unanswered question: What story, exactly?

Reach Joshua Kosman: jkosman@sfchronicle.com