In Terrence McNally's "Mothers and Sons," a taut, terrific new play getting the world-premiere it deserves at Bucks County Playhouse, values and perspectives clash for the entire 80 minutes and the tension constantly percolates.

The production stars Tyne Daly with an A-one cast. With this debut work, the revived playhouse begins to resemble its old and celebrated self.

"Mothers and Sons" is McNally's update, more or less, of a TV play he wrote in 1990, before he'd won any of his four Tony Awards for playwriting ("Master Class," "Love! Valour! Compassion!" and the books for the musicals "Kiss of the Spider Woman" and "Ragtime"). His teleplay, "Andre's Mother," ran in 1990 on the former PBS series, "American Playhouse," and involved Katharine, who could not accept her son Andre as a gay man, or his death from AIDS, or his partner named Cal.

Fast-forward about a quarter-century to present time, and McNally delivers "Mothers and Sons." Katharine (Tony winner Daly, in a genuine and nuanced performance) has come from her Texas home to Manhattan, and drops in unannounced on Cal (the excellent Manoel Felciano). Cal is now a married gay man who, with his husband, has a six-year-old son (impressive child actor Grayson Taylor).

Cal and Katharine haven't seen one another since Andre's funeral. She ostensibly wants to drop off something of Andre's that she'd been keeping. Cal is totally unprepared for her appearance.

Twenty-five years is a long time. Cal now lives in a state where his ability to marry another man is law. Being gay does not necessarily carry a life-wrecking stigma, and AIDS remains a dreaded danger yet not a sure-fire death sentence. The world changes. Do people?

"People don't change," Katharine tells Cal at one point. "That's one of the lies we tell ourselves." She has been setting herself in stone for much of their visit. "We all play parts," she says. "Some of them we play so long and so well, we can't play anything else."

That's not acceptable to Cal or his spouse, the younger Will (Bobby Steggert, also top-notch), who now live openly and with the same status as any couple with rings, love and eventually kids. For them, the years since Andre died have brought benefits that change their notion of who they can be. For Katharine, those benefits are liabilities; somehow her son was murdered, somehow the murderers became respectable.

And so, their conversation ensues. "Mothers and Sons" is strikingly real in the characters McNally creates – none of them is loaded, overdrawn or stereotyped. If you know a wide variety of people, you may know all three. McNally manages to cover a lot of territory in the characters' back and forth, everything from acceptance and denial to vengeance and redemption.

For me, though, McNally's triumph here is the way he approaches the fragile conversation he creates between these characters – like a journalist laying out two complete, and completely different, sides of a story. Katharine and the two men she visits, or maybe intrudes upon, all get to state their cases clearly, no punches pulled, no author's message weighing them down. The denoument comes as naturally as the discourse that precedes it.

The theatrical genesis of "Mother and Sons" is an old-fashioned one: plain and simple and without workshops or staged readings or a long list of backers putting their mouths where their money is. Over the winter, Bucks County Playhouse producing director Jed Bernstein – who leaves next year to become president of Lincoln Center – asked McNally if he'd be interested in writing a piece to open at the playhouse, in New Hope. McNally had been contemplating "Mothers and Sons" and agreed.

Bernstein hired a director (Sheryl Kaller, who staged "Next Fall" a few seasons back on Broadway and gives "Mothers and Sons" a fluid pacing), assembled a cast and designers (Wilson Chin's apartment set is a knockout), jumped into rehearsals three weeks ago in New York, moved to Bucks County for final work this past week and, well, let's put on a show.

Which they do, impeccably.
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"Mothers and Sons" runs through June 23 at Bucks County Playhouse, 70 South Main Street, New Hope. 215-862-2121 or www.bcptheater.org.