Human fralities take the place of heroism, meriting compassion and forgiveness -- not least when dealing with marriage. Such observations lie at the marrow of Terrance McNally's slow Chekhovian exploration of the difficulty, perhaps the impossibility, of maintaining a relationship without secrets, reservations or concessions. For everyone has something to conceal among the two couples celebrating the Fourth of July at a Fire Island beachhouse. Gordon McConnell as the overbearing John and Oscar Cheda as the woebegone Sam are both excellent. But top honors go to Angie Radosh as Chloe, whose blithering exterior masks deep wounds, and Patti Gardner, who simply has never been better as a woman mourning her brother and the marriage she once hoped for.