Quietly wonderful moments abound in "Two Sisters and a Piano", Nilo Cruz's new play at the Public Theater about a pair of restless young women under house arrest in Castro's Cuba. The play's overall impact is ultimately slender, but some first-rate acting, particularly from "Rent" alumna Daphne Rubin-Vega, adds fuel to the play's softly undulating emotional heat.

Rubin-Vega plays Sofia, who shares with her sister Maria Celia (Adriana Sevan) a formerly grand Havana house haunted by the ghosts of departed family and friends. The year is 1991, but time has stopped for Sofia and Maria Celia. They have just been releasedfrom prison, and are forbidden to leave the house or receive visitors. Maria Celia's writing is the cause of their persecution by the Castro regime, although pianist Sofia happily affixed her signature to the manifesto her sister penned at a moment when new freedoms seemed a possibility. Now, while Sofia scavenges moments of pleasure by listening to the movements of the man next door, Maria Celia broods over unanswered letters to her husband, in exile in Europe.

The sisters' ruminations on absent men are interrupted one day by a pair of visits from real ones, the first an army lieutenant who professes an admiration for Maria Celia's stories, and offers to read her husband's confiscated letters if Maria Celia will spin a fresh talc for him.

Sofia, meanwhile, blossoms flirtatiously in the presence of the handsome young man who has come to tune the piano. The play, too, blooms beautifully in this scene, as Sofia and Victor Manuel (Gary Perez) talk of the music they love, and Victor overflows with glee at the pair of shoes Sofia offers in lieu of payment.

Perez wonderfully conveys the jittery, delirious excitement that such a humble acquisition can inspire in a soul long attuned to deprivation; Sofia, meanwhile, is giving a little piece of her affection-starved heart with the shoes, and the subtle miscommunication involved in their exchange leaves a heartbreaking afterglow.

"Please, stay with me a while longer," Sofia pleads, and Rubin-Vega beautifully reveals the raw feeling that Sofia can't quite conceal. Indeed, there isn't a moment of false feeling or opaqueness in Rubin-Vega's extraordinarily vibrant performance. From moment to moment, it's alive with conflicting feelings - childish anger at the tedium of knit-ling, the sisters' lone source of income; desperate loneliness that leads her to desperate acts; pent-up anger at her sister, whom she blames for their predicament; bitter resentment for years of life sacrificed to ideas she was too young to understand.

Maria Celia, unfortunately, is a less multidimensional character. Her tight-lipped pride and defiant forti tude is conscientiously conveyed by Sevan, but there aren't many notes in the performance or the writing. And the one other element is obvious: It's clear early on that Maria Celia's high-handed, contemptuous treatment of her army admirer will give way to something rather more torrid, and so it does.

Cruz's writing for the relationship between Maria Celia and her lieutenant, in which lust and loneliness rather predictably get the better of politics, is not his strongest. Nor is Paul Calderon's performance as the ardent lieutenant all it could be. The pair make a very stiff couple, and the second act's concentration on their relationship threatens to dispel the play's gentler, more subtle perfumes.

These surround the relationship between the sisters, and Cruz's writing and Loretta Greco's direction are at their most sensitive in delineating the emotional complications the sisters' mutual dependence involves.

The evening's most breathtaking moment is a silent one that opens the second act. Dressed in finery inherited from their mother, the sisters are awaiting the promised return of the piano tuner. Time passes; he doesn't come. They rise to dance, hungry for diversion. Locked together, moving to the music, they gaze abstractedly over each other's shoulder, lost in individual reveries of happier pasts and hoped-for futures. They cleave to each other with an almost animal affection, a mixture of loneliness, pure sensual pleasure, sisterly love. But even as they cling together with desperate affection, the solitude inscribed on their faces only deepens.

--Charles Isher Wood DAILY VARIETY GOTHAM