SAN FRANCISCO (AP) — An uneasy orchestral prelude sets the mood: muffled percussion, brooding woodwinds, anguished strings. The curtain rises and the first voices we hear are of two young men cowering in the shadows.

“I … I … I can’t ….go to work,” one stammers in German.

“I can’t board a plane … I can’t sit with my back to the door,” another says in Spanish.

They are living ghosts, traumatized survivors of a school shooting that occurred 10 years earlier, but the memory of which intrudes like an unwelcome guest on a wedding celebration taking place in the present.

So begins “Innocence,” the last opera by Finnish composer Kaija Saariaho, who died of brain cancer last year. First seen at the Aix-en-Provence festival in France in 2021, it is now receiving its U.S. premiere in San Francisco beginning June 1.

For 100 intermission-less minutes on a split-level rotating set, the two worlds play out, separately at first but gradually intertwining as we learn the tragic connections between the bridegroom’s family and the long-ago events at an international school.

“She wanted to create a kind of thriller,” said Clément Mao-Takacs, who will conduct the opera in the San Francisco Opera. “It’s very focused, which keeps the audience’s mouths wide open and the heart beating from the first note.”

As for the score, Louise Bakker, who is directing the production, said Saariaho had created “atmosphere as much as music.

“Don’t expect long, romantic Puccini melodies,” she said. “That’s not what this is at all. But the beauty of this piece is in its truth and in its precision and what you can bring from that.”

Simon Stone, who directed the premiere and will oversee the production when it arrives at the Metropolitan Opera in a future season, said the revolving set helps make audience members feel they are discovering the links between past and present for themselves.

“I thought if I could turn the restaurant where the banquet is happening into the school slowly, gradually, throughout the production,” he said, “without the audience noticing, that they could be dragged into the same sense of intractable grief that the characters felt.”

If that grief is palpable, less clear is the “innocence” of the title. It turns out no one in the story is without some responsibility, not even the waitress whose daughter was one of the victims and who is working at the banquet unaware the family’s older son was the shooter.

“Innocence is what’s killed when an event like this happens,” Stone said.

Curiously, Saariaho’s initial idea for the opera stemmed from Da Vinci’s fresco of “The Last Supper.”

Matthew Shilvock, the San Francisco Opera’s general director, recalls first hearing about the project over dinner with Saariaho in 2015.

“Kaija was fascinated about the mindset of each of the 13 people around the table,” he wrote in an article on the company’s website. “A group brought together in a moment of deep emotional impact, but each bringing their own perspective, history and reality.”

From this kernel, Saariaho and her librettist, Finnish novelist Sofi Oksanen, developed the scenario, which has 13 singing or speaking roles: seven at the school and six at the wedding banquet. As if to underscore the different understanding each character brings to the events, nine different languages are used in the libretto.

Finland has not been immune from school shootings, with the worst of them being two that resulted in mass casualties in 2007 and 2008. But the prevalence of gun violence in the U.S. makes the subject especially sensitive here.

“I wonder how American audiences will cope with its unsparing approach to a subject that, for several decades, has been locked in accelerating cycles of national insanity,” critic Alex Ross wrote in The New Yorker after the opera’s premiere in 2021. “No false tone of healing or hope is sounded at the end; instead, the circles of complicity keep widening. What rescues the opera from utter bleakness is the inherent beauty of Saariaho’s writing.”

Acknowledging the sensitive nature of the topic, the SFO has put together a series of panel discussions and community outreach events focusing on such subjects as gun violence and “depicting trauma on stage, screen and in music.”

Despite the subject matter, there’s a sense of things coming full circle in having the U.S. premiere take place in San Francisco. It was here, in 2018, again with Mao-Takacs conducting, that music from the opera was first performed by an orchestra.

Shilvock had arranged for the company’s musicians to record excerpts so the creative team could experience the opera’s “sound world.” Saariaho was on hand in the auditorium.

“It was crazy, and really moving,” Mao-Takacs recalled. “I will always remember the look of Kaija when I turned to her, and I was in the pit in the big empty hall and I said, ‘What did you think?’

“And she had this beautiful sentence: ‘It sounds like I want it,’” he said. “She was expressing her joy in the orchestra sounding well, her pride in having been able to write exactly what she had in mind.”