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.