Marsha Norman’s “‘night, Mother” works from a premise of sadistically tear-jerking brilliance. On some humdrum night, middle-aged Jessie tidies up the house she shares with her mother, Thelma. She refills candy jars, takes out the trash. Also she mentions that she plans to kill herself, that very night. And there’s nothing mom can do about it.

At this point the play is maybe 10 minutes old. What remains, for the other 80, is a diabolical challenge for Ms. Norman, the director, and two very brave actresses. Why doesn’t Mom just tackle her, or take a frying pan to the side of her self-annihilating head? (Tough love, sure, but under the circumstances….) As an actor, how do you make these women convincing in the most extreme circumstances, and sustain them for the whole show – not just a moment of truth, but an hour and a half of truth? Almost everything about this play is the stage equivalent of skiing up the mountain: Exceptionally tricky to pull off, but good God – consider the triumph if it works.

Mostly it doesn’t. At least not at the Royale, where a new revival opened last night under Michael Mayer’s direction. It’s one of the grave disappointments of the year. Handed an enormously potent script and two extraordinary actresses, Edie Falco and Brenda Blethyn, his production realizes only a morsel of its potential. Should we speak meteorologically? The hurricane missed. What might have devastated has left everyone merely damp.

Ms. Falco is one of the subtlest and most sure-footed actresses now working. Just about every episode of “The Sopranos” confirms this. Her acting in the episode where Carmela and Tony split up is the most astonishing piece of television acting I’ve seen. All the emotional summits were reached – sometimes so much rage or despair Carmela couldn’t even speak – but the performance never felt showy or histrionic.

That resoluteness sometimes betrays Ms. Falco here. Jessie has plenty of reason for sorrow: a beloved father gone, a husband fled, a son turned to crime, a mother who requires constant attention, but supplies little joy. She was badly hurt in a riding accident, and this is on top of her epilepsy. But one of Ms. Norman’s ingenious twists is to make Jessie thoroughly sane. Her state of mind has been altered in the past year, but she has more clarity now, not less. If she chooses suicide, it is with open eyes, no illusions. It is, she feels, the only option left to her, and she sees no reason not to exercise it. Ms. Norman fills her 80 minutes with plenty of revelations, and different gambits on Thelma’s part to stop her daughter. Yet Ms. Falco never seems to waver, never teases us with the possibility that her mother might win.

The trouble seems to lie in the direction. Mr. Mayer deserves a little defending: It’s daunting to navigate all the climaxes and quiet moments in this play, to calibrate the pace and tension, the arcs within its arcs. But his stage business is more hectic than lyrical, and the tension often nonexistent. Considering how much is at stake for these women, this play should never be dull. So why did my eyes keep straying to the clock at stage left, ticking off the minutes in real time?

The quality that Ms. Norman’s play most needs, and that Mr. Mayer most fails to provide, is intimacy. (“There is a familiarity between these two women that comes from having lived together for a long time,” writes Ms. Norman.) Delicate yet forceful, Ms. Blethyn is one of the prides of her nation. Unfortunately that nation is Great Britain. The accent she adopts here – an elusive, swing-state twang – proves hugely distracting. The drawl sometimes sounds, if you please, like a motherly John Wayne.

Ms. Falco fares no better. On screen and stage (as in “Frankie and Johnny in the Clair de Lune”),I have seen Ms. Falco excel often, and occasionally come up short. This is the first time I have seen her uncomfortable, straining. At least she makes the decision (or wisely follows the instinct) to shed the accent for moments of intensity here and there. The question hovers: Just this once, couldn’t the Cates family hail from Scranton?

The Royale is not an especially big theater. Still Ms. Falco and Ms. Blethyn spend much of the evening shouting at each other. It further erodes the play’s intimacy, and gets exhausting. It also weakens the moments when Jessie and Thelma really do need to shout at each other. Without exception the best moments are quiet ones. When Ms. Falco describes how she and her husband tear themselves apart inside their son, or Ms. Blethyn, telephone in hand, decides not to call for help after all, the show achieves a sudden, haunting power. This revival could have been, and should have been, overwhelming.

Neil Patel’s scenery for the Cates home is sufficiently soul-crushing in shades of tan and brown. The impersonal direction and straining vocal cords suggest the set may have been twice as effective if half as big. At the end, when Thelma has run out of arguments, and Jessie prepares to make her last trip to her bedroom, its door suddenly looms. A previously unremarkable slab of wood seems to grow, darken, turn positively demonic. The tension built over the past 90 minutes has something to do with the metamorphosis, to be sure. It may also be that lighting designer Brian MacDevitt has worked more of his subtle magic upon the stage.