Since Agamemnon and Clytemnestra were at their Attic — and antic — best families in a fix have been a major source of raw material for creative artists. Thus it’s easy to understand Jake Heggie’s fascination with the Mitchells — mother “Maddy,” an ageing actress, her gay son Charlie and daughter Bea, wife of a wayward husband, the subject of “Last Acts,” a chamber opera premiered by the Houston Grand Opera on February 29.

The Mitchells are something of a special case, for not only are they a mess as a group, but individually as well. “Maddy” has concealed her husband’s suicide from her estranged children. Charlie, the younger, watches his partner die of AIDS, while Bea — her kids already in college — laments her husband’s philandering. Heggie found the Mitchells — the deceased husband, although absent from the work, is still part of the family — in “Christmas Letters,” a 2001 play by his frequent librettist Terrence McNally that was given a single reading at a New York AIDS benefit. Smitten by the story, the composer asked Gene Scheer to fashion a libretto from McNally’s text.

When Heggie is on stage there’s no “Capriccio”-style clamor — “prima la musica e poi le parole” — about words versus music. He’s a setter of words, a composer first of songs and then of operas and musical scenes, in which the text comes first. The new score is smooth and flows without huge ups and downs; an occasional nudge of dissonance might have made listeners more aware of the finely-wrought music they are hearing. Heggie makes it too easy for the audience, drawing them into the story with his refined sense of theater and allowing them to overlook the sophisticated music that he has written.

A young composer could not have wished for better on-the-job training than Heggie got when he joined the press wing of the San Francisco Opera in 1994. Just out of college with a stack of early songs under his arm, he was immediately involved in the company’s 1994 world premiere of Conrad Susa’s “Dangerous Liaisons.” It helped him hone the skills that led to the SFO commission — and premiere — of his “Dead Man Walking” in 2000. (It remains the most successful opera of the new century thus far.) And the star of the Susa cast was Frederica von Stade, who became Heggie’s friend, muse and mentor. Heggie pays homage to the legendary mezzo in “Last Acts,“ a two-hour study of the Mitchells’ woes.

Tailor-made for her, von Stade is in her element in “Last Acts,” performed on a largely bare stage with an ensemble of 11 instrumentalists on risers behind her. Cesar Galindo provided her with sumptuous gowns, and Brian Nason‘s lighting added to the effectiveness of shifting scenes. Von Stade relishes “Maddy” and she accounted for the success that the work was in the eyes — and ears — of the opening-night audience that packed the 1000-seat Cullen Theater in Houston’s Wortham Center. Indeed, if there is an inherent weakness in the work, it is in the undiminished vocal splendor and still ravishing beauty of the famous mezzo, for von Stade — now 62 — will never grow old. And although Heggie admits that he can see others in the role, “Last Acts” will survive probably only as long as von Stade is able to sing it, for the work is so uniquely hers.

In his HGO debut youthful baritone Keith Phares was a troubled Charlie, while Kristin Clayton was a trifle too matronly to be the daughter of ageless von Stade. “Last Acts” is more Broadway than Berlioz, and von Stade’s first-act “number” is the “hit” of the work. And while the opening act is somewhat bland, Heggie’s skill comes to the fore as the previously concealed truth about the suicide of husband/father is revealed in the second. In the well-balanced score each of the children has a major solo scene. Heggie writes “big” music, even when composing for chamber forces. “Last Acts” is lush and listenable, warm and warming; it’s accessible and affirmative in gesture. Although “Maddy,” affirming that it’s the truth that makes us free, concludes that everything “is going to be alright,” one must wonder whether Heggie — and Scheer — have not made things a bit too simple.

The audience is asked to accept that “Maddy” went on stage to put food on the table and shoes on little feet. No one asks whether she, convinced that “truth could only be touched by imagination,” was in the beginning the constant wife of which everyone dreams. Did she perhaps conceal too much in finding “a version of our lives that we could all live with?” Does “Last Acts” suggest that there is a [italics] truth, rather than the [italics]? Is this not rather a further “take” on life as a stage, in which fiction substitutes for fact? (Not to be overlooked, of course, is the fact that Heggie’s father killed himself when his son was 10.)

HGO music director Patrick Summers conducted from one piano; Heggie was at a second.

Commissioned by the HGO in association with San Francisco Opera and Cal Performances, “Last Acts” will be titled “Three Decembers” in future performances. Heggie has been commissioned to write a new work on “Moby-Dick” to open the Margot and Bill Winspear Opera House, the new home of Dallas Opera, on April 30, 2010.

Wes Blomster