Glimpses of the Moon is a new but charmingly old-fashioned "jazz age musical." Based on a novel by Edith Wharton, it was written specifically for the Algonquin Hotel's famous Oak Room. As soon as we hear composer John Mercurio's first, Gershiwinian piano chords and see Lisa Zinni's authentic-looking costumes, we settle comfortably into the 1920s, and the bright-eyed cast and almost Wodehouse-like plot do nothing to dispel the spell.

A musical comedy of manners, Glimpses tells a jaunty little story that's very specific to its time. In the Roaring Twenties, divorce was newly acceptable. almost fashionable, and women in particular were beginning to wriggle out of some of the chains of social convention. Susy Branch (Xanadu's Patti Murin) and the perfectly named Nick Lansing (Stephen Plunkett, with Michael Minarek taking over on Feb. 19) are moneyless social climbers who've attached themselves rather precariously to high society. Their scheme, to marry for convenience and live off their pricey wedding gifts until they can find wealthy "real" spouses, intersects with the lives of their high-living friends, who include Streffy, a British fop with little money but a handy property in Maine, and Ellie and Nelson Vanderlyn, a rich older couple with a New York City brownstone and a Newport mansion.

If you're envisioning elaborate sets, stop. There are no sets, not even a stage, just a small space in front of the piano. The Oak Room is a cabaret supper club, not a theater. This is pointed up during the number "Right Here, Right Now," set at the Oak Room itself (of 1922) and sung by a different guest performer at each show. (Last night it was KT Sullivan; Susan Lucci and Joyce DeWitt are among those coming up.)

Director Marc Bruni uses the small central space and the room's shape cleverly, keeping the action tightly controlled and more or less intelligible, though those seated at the far ends of the room may have missed some of the lyrics during the faster sections. In general the actors' unamplified voices carried Tajlei Levis's witty lyrics loudly enough, which is important, for they are sharp and precise, with occasionally Cowardly turns of phrase.