Murder, love and the possibility of redemption behind bars are the themes of "Dead Man Walking," the powerful opera by Jake Heggie and Terrence McNally that Minnesota Opera is presenting through the weekend. It shouldn't be missed.

The opera is based on the bestselling 1993 memoir by Sister Helen Prejean, which tells of eye-opening experiences on Louisiana's death row. It concentrates on her relationship with a man convicted of taking part in the murders of two teenagers abducted from a lovers' lane.

The book was made into an award-winning 1995 film starring Sean Penn and Susan Sarandon. Although the opera version, premiered in San Francisco in 2000, was a first effort for its creators — Heggie was known chiefly as a songwriter and McNally a playwright — it has more than 50 productions worldwide to its credit, making it the most often-produced American opera of the 21st century.

The work's virtues — its dramatic force, tight construction and telling moments of sadness and yearning — are made abundantly clear in this thoughtful, often gripping, production from Vancouver Opera with vivid staging by Joel Ivany and deft pacing by conductor Michael Christie.

McNally's libretto is theatrical yet always direct and believable. The opera's two acts build effortlessly toward stunning climaxes. McNally's central male character, Joe de Rocher, is fictional, a composite of several prisoners we meet in Sister Helen's book. (The work's title, Sister Helen tells us, comes from San Quentin, where the guards called out "Dead Man Walking" when a death-row inmate leaves his cell.)

Heggie, it turns out, is a dramatic composer of assurance and substance who has composed several more operas since 2000. Not only does he set words clearly, but his music , a web of arias, ensembles and choruses, all in a largely tonal, lyrical but never sentimental style, moves the action along with a strong sense of flow. Heggie uses motifs skillfully, and his handling of popular idioms — blues, gospel, rock 'n' roll — comes across as natural. The big choral number at the end, a dirge with pounding inevitability, acts as a final outcry for justice and compassion.

Designer Erhard Rom's two-level set effectively evokes the sterility of a prison, ugly and ominous. The persistent presence of a huge U.S. flag on an upstage wall reminds us that capital punishment, at least in the Western world, is an American practice. Sheila White designed the effective costumes and Jax Messenger the lights.

It's hard to imagine a stronger or more dramatically apt cast. A resonant baritone, Seth Carico made Joe a fierce, gritty, ultimately vulnerable and frightened character. Carico's "Warm Night" aria hit just the right tone of sensuality. Catherine Martin's Sister Helen displays a similar kaleidoscope of emotions in a thoroughly convincing and beautifully sung performance.

They make it clear that a kind of love develops between their characters, and their love is the spine of the story. Commentators on the book, the movie and the opera have been eager to deny that there is a romantic element to this love between nun and condemned man, even though it's there so obviously. ("Part of me will die when you do, Joe," says Sister Helen.)

There were moments of truly impressive singing on opening night from Karen Slack (Sister Rose) and Emily Pulley (Joe's mother). The victims' parents, too, were excellent: Andrew Wilkowske cq and Mary Evelyn Hangley cq as the Harts and Robb Asklof cq and Victoria Vargas cq as the Bouchers cq. Andres Acosta cq was the droll traffic cop. The chorus members sang with rich resonance and dramatic conviction.

There was one mistake in Ivany's staging: Joe's final words to the parents at his execution — his plea for forgiveness — couldn't be heard because Carico was strapped in and lying down. These are the most important words in the opera. They need to be heard or else put on the surtitles above the stage.

The work's authors have always insisted that the opera takes no stand for or against capital punishment. Surely this is false. Ultimately, the opera and the book, without excusing the crimes, see Joe as a victim. Sister Helen makes her objection to capital punishment clear in her book. She poses the question: "By killing the killer, are we creating 'justice' or are we creating another victimized family?"

Michael Anthony is a Minneapolis writer.