The opera hews closely to the novel during Act I. The young man becomes a favorite of Queen Elizabeth; experiences heartbreak during the Great Frost of 1608; and writes poetry, hoping to share it with a celebrity in the field, Nicholas Greene (the baritone Leigh Melrose, with vocal swings reminiscent of Mr. Eddy in Ms. Neuwirth’s “Lost Highway”). Presiding over all this is the Guardian Angel: Eric Jurenas, whose smooth and full-bodied countertenor was a highlight.

Orlando becomes an ambassador abroad, where one day he wakes up as a woman — in a rose-and-mint dress with a mane-like collar of flowers — and the effectively second-class life that comes with that new gender. By the end of Act I, in a departure from the novel and the beginning of the opera’s more glaring politics, she speaks of sexual abuses against children in Victorian-era Britain and vows to rewrite history for women.

It’s a hefty promise for Act II, and Ms. Neuwirth never quite delivers on it. We meet Shelmerdine, Orlando’s husband-to-be (Mr. Melrose again), who shares her mid-length wavy hair and angular features — and, eventually, her child, played by Mx. Bond (who prefers that gender-neutral honorific). Then the plot speeds through the 20th century in a prolonged montage of a world in which swords have been replaced by atomic bombs, and boundaries of identity have been torn down like the Berlin Wall.

The action comes to a standstill once, during World War II, when Orlando stands alone on the empty stage as the names of victims of the Holocaust are projected on curtains; the score samples a 1928 recording of the slow movement from Bach’s double violin concerto, played by Arnold Rosé and his daughter Alma, who died at the Birkenau concentration camp in 1944. A slowly building alarm creeps into the rending music, then the stage is cleared with a sonic blast — one so powerful it shakes the seats of the theater. As the dust settles, so to speak, the onstage screens show the bombed-out Vienna State Opera in the aftermath of the war.