Staging Terrence McNally's "Master Class" can be a risky proposition.

Success depends primarily on the strength of one person, the lead actress, who must spend two hours pretending to extemporize solo as larger-than-life soprano Maria Callas.

Happily, Oyster Mill Playhouse, where the show opened last weekend in a production directed by Fran Horkowitz, has found its star.

Jody Brinley is a natural as Callas.  She inhabits the character completely, holding both her "victims" (her students) and her onlookers in an unbroken spell.

McNally's convention in "Master Class" is unusual.  Callas drills three young opera singers and addresses an audience ostensibly composed of other music students.

But the process turns into an exposition on the teacher as excerpts from operas by Verdi and Bellini spark Callas' memories of her humble beginnings, her triumphs at La Scala, and her troubled relationship with millionaire Aristotle Onassis.

Brinley appears entirely at ease in the role. She delivers her lines, even those whole passages in Italian, with expert timing and depth of understanding.  It's a pleasure to hear the musical lilt of her commands, as when she orders one singer to "Feel! Be! That's what we're doing here."

Jamie Ensinger is a fawning, goody-two-shoes version of soprano Sophie de Palma.  She is the first to enter Callas' lair and the only one to be defeated by it.

Angela Ruediger and Carlo Stebbings play more secure characters, soprano Sharon Graham and tenor Tony Candolino.  Nearly beaten down by Callas, they rally enough "Mut" (German for "courage") to impress and, in Graham's case, fight back.

They also get to sing the most, Ruediger an impassioned reading of the letter scene from Verdi's "Macbeth" and Stebbings, a graceful account of an aria from Puccini's "Tosca."  Art Thompson plays Manny the accompanist and C.J. Coolson is the exasperated stage hand.

Callas the woman turns out to be far more complex than her stereotype as a prima donna extraordinaire.  But, as the character says so often, "that's another story."

ZACHARY LEWIS: 255-8266 or zlewis@patriot-news.com