A play about a stamp collection? And that's supposed to be interesting, you say?

Well, in the hands of Pawtucket's Sandra Feinstein-Gamm Theatre, Theresa Rebeck's "Mauritius," the tale of two estranged half-sisters wrangling over a potentially valuable stamp collection turns out to be a riveting night of theater.

It's a crisply written play with unexpected twists and turns, with conmen running cons on conmen. And with tight, forward-pushing direction from Rachel Walshe, visiting artistic director at Perishable Theatre, "Mauritius" sings.

It is the death of their mother that has brought half-sisters Jackie and Mary together again. Jackie, the younger, has been left a stamp collection that found its way into her mother's things. Could it be worth something? But Mary claims the collection, amassed by her grandfather, is hers, and she is not willing to part with it.

Jackie could care less about stamps; she's got bills to pay. But Mary is something of a connoisseur, someone attached to the memories the collection evokes, someone wrapped up in its history.

As the play opens, Jackie is trying to interest as small-time dealer, Philip, in taking a look at the collection. But Philip's a crusty sort who refuses. So, up steps a customer named Dennis who has been hanging around Philip's shop. He offers to check out the collection, and what he finds stops him cold -- two incredibly rare stamps issued by the island of Mauritius.

That's when Dennis hatches a scam to get the stamps for a song from an unsuspecting Jackie. He has lined up a buyer, a wealthy businessman and sometimes arms dealer, who doesn't so much as admire stamps as makes love to them. He's a man who won't take no for an answer.

In a somewhat hard-to-believe transformation, Jackie goes from an insecure know-nothing to a shrewd wheeler-dealer who gets the upper hand in the negotiations.

The opening moments of the show were a little awkward opening night, as Amanda Ruggiero's Jackie tried to get the attention of laconic Philip, played by Gamm veteran Jim O'Brien. She just seemed a little uncomfortable. But as the play unfolds, she got more and more convincing. A scene that didn't seem to jell, gives way to tighter and tighter vignettes, as the suspense builds.

Steve Kidd, as Dennis, is the perfect conman -- until the bottom drops out of his plans. He tracks Jackie down, barges into her house, and begins sweet-talking her. When that fails, he switches his attention to Mary and says whatever he has to to win her over. His transformation, from slick operator to sheepish accomplice doesn't quite wash, though.

When Jackie wonders aloud about Dennis' past, asking if he once had money and now has none, she hits a nerve. And Kidd's smug smile begins to melt ever so slowly.

Richard Donelly, as the interested buyer, Sterling, has a compelling few moments in the second act, where he explains the finer points of commerce to Ruggiero, in an intense, searing monologue. He's both beguiling and menacing.

Casey Seymour Kim, another Gamm stalwart, does the honors as Mary, displaying a wide emotional range.

But the action is not all serious. When Sterling offers a suitcase full of cash to Jackie, says it's his final offer, and Jackie begins to leave, he begins pulling wads of bills from his pockets until she agrees to sell.

"Mauritius," which played Broadway for a couple of months in 2007, is a beautifully crafted play, rich with allusions of bad blood between Philip and Sterling, something about a marriage gone bad, and a strained history between Mary and Jackie. But most of Rebeck's characters live in the present. Most of what we know about these people is through watching them deal with greed, mistrust and family fortunes.

But at its core, "Mauritius" is just a heck of a good story that will keep you guessing, even when you think things are going to resolve themselves but continue to unravel.

"Mauritius" runs through Nov. 21 at the Sandra Feinstein-Gamm Theatre, 172 Exchange St., Pawtucket. Tickets are $30-$40. Call (401) 723-4266, or visit www.gammtheatre.org.