Suicide, as it is usually depicted in the theater, is an act of florid melodrama, the final grandiose gesture in a life that has soared too high or plunged too low.

In " 'night, Mother," which opened last night in Arena's Kreeger Theater, it marks the end of an existence that is going no place in particular. It comes after the house has been picked up and the garbage wrapped neatly in a plastic sack; after the cups of cocoa have been prepared and the candy dishes have been refilled and a clean slipcover has been put on the sofa. It is merely one of a number of humdrum tasks to be accomplished before the evening is over.

Nothing, in fact, about the pedestrian surface of Marsha Norman's Pulitzer Prize-winning drama will prepare you for its devastating emotional impact. The two lives she has chosen to chronicle -- a mother's and a daughter's -- would be unexceptional were it not for the fact that the daughter has chosen to end hers. It is not yet 8:15 by the sunburst clock on the living room wall when she calmly announces her decision. By 9:40, she will have locked herself in her bedroom with the gun she's brought down from the attic. The impending deed looms over all the humble minutes in between, making them among the most harrowing ever put on the contemporary stage.

Something huge and horrible is happening. But Arena's exceptional production -- acted with unadorned directness by Halo Wines (as Jessie, the daughter) and Ann Guilbert (Thelma, the mother) and staged with painstaking realism by James C. Nicola -- never overstates its importance. The secret of " 'night, Mother's" power, I think, is that it steadfastly tries to avoid the emotionalism implicit in the subject. Indeed, the mother's first reaction is to scoff. "We're just going to sit around like every other night in the world," she barks in a tone of disbelief, "and then you're going to kill yourself." That, however, is precisely the evening that Norman has in mind -- an evening of passing chatter and accumulated rituals that is just like all the others, except that it is the last one.

Jessie has no deeply buried secrets to spill, no rancors to exorcise, no last-minute explanations to justify her behavior. She does have a history of epilepsy, but the seizures now seem to be under control and she feels better, physically, than she has in years. Although her husband divorced her and her son appears to have embarked on a career of petty crime, she does not hold them responsible.

To the extent that she can articulate them, the reasons for her suicide do not lie in her biography but rather in the lack of one. Her life, she feels, never really happened. The person she was supposed to be failed to show up. Now she's tired and "just not having a very good time." She would, however, like to make things as easy as possible for her mother. The real business of the evening, as she sees it, is to tell her where the fuses are kept, how to order the groceries, what number to call if the washer goes on the fritz and, oh yes, what to say to those relatives who show up at the funeral.

As the reality of the situation sets in, the mother fights back with every tactic in her limited arsenal -- from mockery to abject pleading to petulant displays of anger. "I'll teach you to crochet," she even proposes at one point with forced enthusiasm. The mounting desperation is hers, and Guilbert plays it with such crackling vigor that her capitulation to the inevitable comes like a second death. In the play's most touching scene, Jessie brings out a cardboard box of gift-wrapped packages -- "little presents for whenever you need one," she explains with a shrug that wants to be an embrace. Through her gathering tears, the mother's eyes light up despite herself. The roles have momentarily been reversed: The parent has become the child, and the child the protective parent.

Every suicide leaves the living wondering "Why? What could I have done?" Norman's plays suggest that no one can answer those questions -- the victim no better than the survivors. The most you can say is that for Jessie suicide is an act whose time has come, that her need to say "no" is stronger than her ability to say "yes." Hamlet may be compelled to contemplate the troubling proposition, "To be or not to be." " 'night, Mother" asks what do you do with the dishes. Step by wrenching step, it ushers us through the minutiae of a leave-taking. To the bitter end, it is concerned with bedroom slippers and the dirty cocoa pan and the chinaberry red nail polish that might have given a touch of novelty to the usual Saturday night manicure. Minutes before she kills herself, the daughter is washing her hands at the kitchen sink, neatly drying them with paper toweling and carefully rubbing in hand lotion.

Wines looks almost anonymous in the role: Her hair, unflatteringly straight, falls away from her wan face like rain, and she is dressed in baggy corduroys and a scratchy sweater. But the actress finds so many fine shadings -- even the glimmers of love -- in Jessie's dull gray soul that the character becomes unique. Guilbert knows that the mother, a farmer's wife, is not a smart woman -- but she can be shrewd and funny, and there is bedrock gallantry in her attempts to stop the unstoppable. The ruthless honesty of the performances leaves scorch marks on the stage.

Russell Metheny has meticulously recreated their nest -- the spic-and-span kitchen that is striving to stay abreast of the latest convenience; the living room that gave up its pretensions to taste when the sewing machine was moved in. Everything from the afghan on the sofa to the blender on the counter has its place -- except the occupants. Realistic as it is, the set adds a fiercely ironic commentary of its own. It desperately aspires to middle-class comfort. And in " 'night, Mother," there is none.