With the chamber orchestra onstage (and becoming part of the action in a hilarious scene), under the baton of Jonathan Khuner, attention is divided between singers and instrumentalists, but Shearer’s music is such that even if the orchestra were hidden, the listener would be aware of it – and that’s a good thing.

Somewhat reminiscent of “The Rake’s Progress,” the orchestra here doesn’t accompany the singers, but is at variance with them in the manner of a concerto, voices vying with the orchestra, but in a friendly, supportive way.

Shearer’s music is pleasantly dissonant, with a sound that sticks in the ears and memory. It’s ambiguous music, seemingly wondering between keys, but landing securely each time. There is an element of choppiness in the first act, short phrases chasing each other, but the second act settles down, taking deeper breaths, and culminating in a memorable finale, an upbeat variation on the cast of “Don Giovanni” facing the audience.

With apologies to the wonderful cast, first credit should go to the musicians: pianist Karen Rosenak, violinists Barbara Riccardi and David Cheng, violist Stephanie Ng, pride-of-town cellist Thalia Moore, a (one) handful of woodwinds and brass, and multitasking percussionist Mckenzie Camp (of stentorian voice) all respond to Khuner’s direction with consistent excellence throughout the work’s two-hour length.

On stage – with Mathew Antaky’s simple and terrific set and lighting design; Jeremy Knight’s striking (but not distracting) projections; and Christine Crook’s period-perfect costumes – Sara Duchovnay’s Dorothea, Tonia D’Amelio’s Celia, Daniel Curran’s Ladislaw, Eugene Brancoveanu’s Chettam, Michael Mendelsohn’s Brooke, and – receiving a huge chorus of good-natured boos for making the tiresome evil Casaubon alive – the great bass Philip Skinner all shine individually and meld into a believable ensemble.

Phil Lowery is the stage director, not only moving the actors around well, but executing a third-wall surprise (which could have gone south easily) boldly and well as the orchestra participates in the election scene, arguing, shouting, and throwing vegetables at the politicians – it’s hilarious and fits into the piece, even such anachronistic bits as shouts of “Right on!”

Shearer had said while preparing the work that “It was very exciting to embark on this. Dorothea’s disastrous marriage, and how she later gives up her dreams to follow her heart–this is the stuff of opera. From it we constructed a dynamic arc. And it is not merely a love story. It plays out against a rigid class structure, greed, pettiness and political gridlock. It speaks to our own time.”

He met the challenge well, as did Stevens, who spoke of the task before her: “To bring this great novel to life as an opera for a modern audience is to relive it totally, rediscover its power and timeless eloquence.”

All done, all in. Kudos all around. There are only three performances left, on March 20-22.