"My Sister in This House" culminates in the ferocious slaughter of a fussy Frenchwoman and her vapid daughter by their two maids, whose servile psyches have been pushed to the breaking point.

You won't see the actual deed. Instead, playwright Wendy Kesselman concentrates, in 16 cool, clinically objective scenes, on the apparently piddling and unrelated events that preface the bloody revolt. Drawing on a real-life murder case in Le Mans, France, in 1933 (the same one that inspired Jean Genet's "The Maids"), she has produced a strange, oblique and disturbing play that is less interested in giving us clear-cut motives than in creating a suffocating climate of repression and incest.

That climate is rendered with considerable effectiveness at the Studio Theatre, which has assembled one of its best casts in seasons to sound out this drama of buried rage. From the stuffy two-story set, a provincial house designed by Russell Metheny with a perfect understanding of bourgeois proprieties, to the sober, unflinching direction by Joy Zinoman, the production represents high-quality work. This, it seems to me, is precisely what our smaller theaters should be doing: plays that coax both performer and audience out of the easy mainstream and point them toward the hidden recesses of the mind.

Kesselman is not about to do your sleuthing for you. She merely observes and records the comings and goings of Christine (Sarah Marshall) and her timorous younger sister Lea (Erika Bogren), whose convent education has drilled them in the ways of subservience. They are hired as maids by the supercilious Madame Danzard (Mikel Lambert), one of those overbearing employers who regularly run the white-glove test on the furniture, count the silverware and treat servants as beasts of burden. But the play is more than a study of the haves versus the have-nots.

Embedded in apparently trivial scenes -- Madame Danzard, whooping it up over a game of double solitaire with her daughter, Isabelle (Julie Frazer); or the maids in their Sunday best, having their picture taken by the town photographer -- are all manner of dark and forbidden impulses. The sisterly bond between the maids will, in this house of adversity, take on boldly sexual overtones. The autocratic attitude of Madame Danzard and her daughter will slowly reveal itself to be riddled with insecurity and weakness. Hate will become part of everyone's daily bread.

What is fascinating about "My Sister in This House" is the way the climate changes without seeming to change. A vase is accidentally dropped. A bonbon is filched from a candy dish. A skirt is ineptly hemmed. A fuse is blown. And suddenly murder is on the doorstep.

With less accomplished actresses, the evening could be mundane in the extreme. At the Studio, however, Zinoman and her cast go for all the unspoken secrets. Marshall, whose considerable talent has been misspent of late in inappropriate roles, taps back into the blunt power she manifested earlier in her career. Her hair has been cropped unflatteringly short and her waifish face is seemingly as nondescript as the dough she kneads savagely in the kitchen. By holding back, however, and continually supressing the turbulence in her soul, Marshall succeeds in raising her performance to fierce dramatic heights. By the end, that sad, lumpen face is a landscape of frustration and pain.

Fourteen-year old Bogren, who up to now has played cute preteen roles, also takes a step forward by cutting back on her natural precocity and retreating into a shell of jumpy diffidence. To ask an actress of so few years to confront the lesbian implications in the work is a decided risk. From all evidence, Bogren is enough of a performer to handle them. Under the circumstances, her fragile and childish countenance further unsettles an unsettling play.

As the horsey daughter, Frazer initially gives every impression that she is her mother's obedient subject. But you'll notice in her adept portrayal little moments of rebellion and irritation. The sides in this domestic war are not so easily drawn as it might appear. Only Lambert, it seems to me, sins on the side of obviousness. She gives us a zesty portrait of a giddy, foolish matron, snapping her fingers imperiously and, when finger-snapping fails to produce the desired results, casting withering stares and spitting out incomprehensible syllables at the maids who have disturbed the order of things in her tight world. But it is too zesty, a flash-in-the-pan performance in a production where the slow, steady smolder is the rule. Half the pyrotechnics would produce twice the effect.

Nonetheless, "My Sister in This House" is the sort of mystery likely to tantalize those who don't demand a last-minute police inspector to pinpoint the moment the worm turned. Like an iceberg, nine-tenths of its matter lies beneath the surface. Kesselman regularly sends sonar waves into the murky depths. But she leaves it to the spectator to imagine the ultimate shapes in that watery dark that is humanity's troubled consciousness.

MY SISTER IN THIS HOUSE. By Wendy Kesselman. Directed by Joy Zinoman; set, Russell Metheny; costumes, Ric Rice; lighting, Dan Wagner. With Sarah Marshall, Erika Bogren, Mikel Lambert, Julie Frazer. At the Studio Theatre through Sept. 30.