Sometimes, you just do not know how a show manages to rivet your attention. Is it the script and the vision of the playwright, or more the vivacity of the production elements? Now running at Act II Playhouse, a memorable revival of  "Grace & Glorie" is a case in point.

You cannot take your eyes off the play's two characters. Grace is a 90-year-old woman who struggles with cancer. Released from hospital, she returns to her backwoods cabin in the Blue Ridge Mountains of Virginia to cherish the remnants of her 500-acre farm and apple orchard.

The other woman is Glorie, a mid-30s transplant from New York City. Formerly a high-flying partner in a Manhattan corporation, she and her husband needed to retreat to a rural life. Independently wealthy, Glorie volunteers for a hostel where she helps guide the dying elderly through their final days.

At one level, "Grace & Glorie" is an odd-couple tale. When we first meet Grace, she lies dancing in bed as she sings an old church hymn, "Throw Out The Lifeline." She is comically puzzled when hospice worker Gloria unexpectedly arrives. She asks, "You volunteer to help people die? Is this some Yankee custom?"

Patricia G. Sabato, the long-time stage manager at Act II, scores in her directorial debut. Parris Bradley's set design is atmospheric. A small wooden cross is centered on the rear wall. Flanking it are a wood-burning stove, an old fridge, a sink and cardboard boxes full of family china, which encircle Grace's bed.

Sabato fills the show with meaningful props, especially the knitted yellow sweater with an apple tree on its bosom. Thanks to the sound design of Adam Danoff, you occasionally hear the menacing bulldozers of a wrecking crew, and the strains of Bluegrass banjos between acts.

Penelope Reed, recipient of the Barrymore Lifetime Achievement Award, plays Grace. She has starred in other Act II shows, most recently as Eleanor Roosevelt in "Eleanor." In playing Grace, her body language is eclipsed by spending so much time in bed, yet she delivers a commanding portrait of a cantankerous old lady who "hates surprises."

Genevieve Perrier, a winner of two Barrymore Awards, complements Reed as the hospice volunteer. Her Glorie is a free-thinking, modern woman full of anger over the personal tragedies she has endured. A steady stream of dress changes by costume designer Janus Stefanowicz suggests Glorie's life is in troubled flux.

Playwright Tom Ziegler has a knack for capturing the anguish of lovelorn women. He achieved that in another play, "Mrs. Kemble's Tempest." In "Grace & Glorie, " you never doubt the authenticity of the two women's anguish and the uneasy way they form a bond.

Though never on stage, you also come to know the men prominent in their lives. Roy, Grace's grandson, drives a pickup truck, a self-absorbed mountaineer who patronizes his grandmother. Likewise, you feel sure that Glorie's husband is an "empty suit" professional. The movie version of "Grace & Glorie" fleshes out many other characters, but Ziegler's lean theater script is powerful in leaving much to the imagination.

Ziegler never resorts to low-brow humor. The show has funny lines that hit the mark because they are faithful to the character. When Glorie declares, "I don't believe in the Devil," impish Grace quips, "Do you think the Devil cares?"

You continually learn new things about the two women. Ziegler plants questions he later answers. When prayerful Grace says she has not been to church for 50 years, you wonder why. Likewise, when Glorie first refers to her Manhattan life, she makes casual references to "the accident" and "the affair."

As the actual lives of the two women emerge, they learn to respect each other and find common ground. By the end of the play, it is intransigent Grace who changes the most. She loses interest in singing church hymns because Glorie "Got me to thinking."

It is easy to visualize a production of "Grace & Glorie" collapsing into sentimentality. Grace gives an actress ample material; you still need the tragicomic timing to make her credible. Turning Glorie into something more than a foil for Grace is a tough slog. The performances of Reed and Perrier are a virtual tutorial on how to partner on stage, and the applause they received on opening night went beyond perfunctory politeness.

While "Grace & Glorie" does not strain to be profound, you recall the Book of Job's core question about the meaning of life amid suffering. It comes to a parable-like ending in Grace's gift of the yellow sweater, and her elegant, recorded speech to grand-niece Luanne on the importance of the solitary stitch.

Act II Playhouse is located at 56 E. Butler Ave. in Ambler. "Grace & Glorie" will run through March 2. Tickets are available at 215-654-0200.