JUST LIKE "every other night in the world," mousy, middle-aged Jessie and her mother Thelma are sitting around their home in Anywhere, America. Then Jessie matter-of-factly announces that she plans to kill herself that evening, with her late father's gun.

Thus abruptly, in " 'night, Mother" at Arena's Kreeger Theater, playwright Marsha Norman sets in motion an emotional tug-of- war between the two women. Norman's Pulitzer-winning two-character play has at its center one of the most dramatically loaded situations the theater can offer.

"I'm just not having a very good time," Jessie explains, as she sets about the house with seemingly detached calm, filling candy dishes, arranging slipcovers, winding clocks. "And I don't have any reason to think it's gonna get anything but worse."

"We won't have more talks like tonight because it's this next part that's made this part so good," Jessie says, and her imminent goodbye prompts questions she's never asked before. The ensuing confession session, between a mother and daughter who thought they knew each other so intimately, is an eye- opener.

Somewhere along the line, Jessie and Thelma switched roles -- now the sweets- loving Thelma is in an almost childlike state of dependence. But Thelma rallies desperately in an effort to save her child's life, trying emotional blackmail, blaming herself, hunting for simple pleasures worth living for -- shopping, rearranging the furniture. "Let's get another dog," she suggests in pathetic earnest. Finally, frustrated by Jessie's determination, she wails, "Forgive me . . . I thought you were mine."

Both actresses are superb, as are James Nicola's sensitive direction and Russell Metheny's carefully detailed, lived-in set.

Gravity pulls Ann Guilbert's heartbreakingly forlorn features earthward, as she embodies Thelma's bewildered impotence. As Jessie, Halo Wines is unrecognizably plain. Her hair brushed straight, her eyes made small and blank, her Jessie is already gone, though her implacable features now and then dissolve into choking emotion till she regains her resolve.

Norman balances her dour material with welcome natural humor, and carefully avoids moralizing about suicide. But because the playwright has developed these two real people so fully, the human consequences of Jessie's "private act" are made achingly clear, and "'night, Mother" settles with a quiet, compassionate weight on the heart.