"We've got a good life here," says Thelma Cates to her daughter, Jessie, in Marsha Norman's new play, "'Night, Mother." Many would agree. Thelma, who is a widow, and Jessie, who is divorced, live together in a spick-and-span house on a country road somewhere in the New South. There are no money problems. Nights are spent in such relaxed pursuits as crocheting and watching television.

But on the particular, ordinary Saturday night that we meet Thelma … and Jessie …, we learn that the good life may not be so good after all. As the daughter prepares to perform her weekly ritual of giving her mother a manicure, she says calmly, almost as a throwaway line, "I'm going to kill myself, Mama." And, over the next 90 minutes, Mama—and the rest of us—must face the fact that Jessie is not kidding….

["'Night, Mother"] is a shattering evening, but it...