By Terrence McNally. Directed by Meg Roe. An Arts Club Theatre production on the Granville Island Stage on Wednesday, October 3. Continues until October 27

Despite having won the Tony and Drama Desk Awards for best new play in 1996, Master Class is not a good script. Playwright Terrence McNally’s portrait of the late-career bel canto diva Maria Callas is built for a showy star turn, but it has no depth. A populist commercial entertainment, it could be subtitled Opera for Dummies. In the script, Callas presents a master class to students at the Juilliard School in the early 1970s. She has blown her voice, so she’s not singing anymore, and her lover Aristotle Onassis has dumped her to marry Jacqueline Kennedy, but Callas soldiers on.

The terms of the play are simple and repetitive. A monstrous egomaniac, Callas condescends to the students, the stagehand, the accompanist, and the audience. Sometimes her arrogance is funny—“How can you have rivals when no one else can do what you do?”—but the note gets replayed ad infinitum. This arrogance covers pain: we get this idea early—and we get it often. There’s little sense of accumulation however, because McNally presents the core of that pain in simplistic terms: Onassis was a vulgar, brutalizing shit and Callas was his victim.

The structure of the play is dull. In Act 1, Callas interrupts her students so much that the frustration of not hearing them sing produces tedium.

And the lesson that Callas teaches, underlines, and repeats is ignored in this mounting. McNally’s Callas insists that opera singers must be able to act—but the vocalists that director Meg Roe has cast are all amateurs in that department. Shannon Chan-Kent, who plays Sophie, Callas’s first victim, is particularly stilted. Melanie Krueger (Sharon) does better and Frédérik Robert (Tony) shares some of this production’s few spontaneous moments with Gina Chiarelli’s Callas. For the most part, though, the singers’ acting performances thud, despite their impressive voices. On the other hand, the work of Angus Kellett, who plays Manny, the accompanist, is wittily understated.

In Act 1, Chiarelli mostly stays on the surface of the already thin script. She commands the stage, but her rhythm seldom varies and, even when Callas acts out the lyrics to an aria and Chiarelli has an opportunity to go a little deeper, she recites the words as opposed to inhabiting them.

Then, in Act 2, Chiarelli gets on a roll. As the play incorporates more singing and more emotional detail, Chiarelli opens Callas’s heart and reveals something of both her own and Callas’s magnitude as artists. Chiarelli’s performance becomes generous and winning.

John Webber’s set, a series of honey-coloured wooden acoustical panels, is simply gorgeous, and Corwin Ferguson’s projection design is exquisite. When Callas goes into her reveries, the lights dim and Ferguson throws washes of moving colour onto Webber’s panels. The moment at which those washes resolved into a grainy slow-motion image of Callas singing was the most thrilling of the night for me.

Still, there’s not a lot of content. Master Class flatters its audience by presenting simplistic representations of opera and the artistic temperament. Don’t fall for them.