Athol Fugard's "A Lesson From Aloes" is a play of terrible beauty.

It is composed of the minutiae of three wasted lives in an arid corner of South Africa, as one sun-scorched day in 1963 eases into an empty, candle-lit night. But it soars with a majesty beyond its seemingly humble means.

In the first act, a sturdy Afrikaner and his fragile wife of English descent are preparing for a dinner party to be held in their dusty garden. In the second act, a single guest shows up -- a black bricklayer who has been persecuted by the government. The dinner party never really gets going; before long, the candles on the wooden table have been snuffed out, the guest has departed on the first leg of his flight to England, and the hosts have retreated to an exile of their own within their stucco bungalow.

The rest is talk -- skittish, brave, wary talk that tries to put up a gallant front but can't ever conceal the fact that three lives are crumbling before our eyes. In a production that seems to gather out of the stillness, like a genie out of smoke, Arena Stage brings dignity and stature to what is surely one of the most important dramas of the past decade.

This is not an evening for the impatient or the inattentive. But Fugard's dramatic equation, once it is established, is so perfectly balanced that subtleties assume the power of cataclysms. A character fumbling with a dinner napkin, a floodlight suddenly switched on, the willful substitution of "if" instead of "when" in a line of dialogue are the equivalent of thunderbolts in a troubled landscape.

Fugard, a South African, has built his drama on the harsh political realities of his country, its apartheid policies and its ruthless treatment of those, white and black, who dare hope for a climate of racial decency. Few plays so thoroughly indict a regime as this one does. And yet "A Lesson From Aloes" does not hurl accusations or call for revolution. It merely shows us three ordinary individuals, whose lives have been brought to a standstill by a country "turgid with violence." Their naked helplessness in the face of rampant inhumanity says it all.

None of them has learned a lesson from the aloes, a thorny cactuslike plant that -- unique among nature's creations, Fugard implies -- survives and even proliferates in South Africa. Piet Bezuidenhout (Stanley Anderson), a farmer until the drought put him out of business, then a bus driver in Port Elizabeth, has taken to collecting varieties of the plant in his garden. Eying them suspiciously, his wife, Gladys, asks, "Is that the price of survival in this country? Thorns and bitterness?" With her polite gentility, Gladys (Halo Wines) would prefer roses. As Fugard unfolds his play, however, it is clear the tortured-looking aloe is a richly apt symbol.

Piet, we discover, was once a fervent fighter for racial justice who believed that "an evil system isn't a natural disaster . . . bad laws and social injustice are man-made and can be unmade by men." But "the cause" has been dismantled, like an obsolete piece of machinery, by a vigilant police force, and in the ensuing climate of mistrust, Piet has come to be suspected (and shunned) by his former comrades as an informer.

Gladys exists precariously just this side of insanity. On a brutal late-night raid, the police confiscated her private diaries, an act of spiritual rape that sent her to the madhouse. There, her mind was "burned brown" by volts of electricity; now, quiet and withdrawn, she seems to wait only for violence to strike again.

Their guest, Steve Daniels (Zakes Mokae), doesn't arrive until mid-play, and then it is with confirmation of the news that he is forsaking South Africa forever. Although he fought by Piet's side for justice, imprisonment and isolation have broken his zeal. There is, he acknowledges sadly, no place in the country for a black man or even his simple childhood memories of fishing by the sea.

In "A Lesson From Aloes," the three are coming together one last time, presumably to say goodbye, but mainly to evaluate the past. Was all the idealism just so much idle talk? There is another level to the questioning, however, and it elevates the play above a treatise on the perils of liberal thinking in South Africa. The characters are all wondering, after the burnout, who they are. What is a man, when the sum of his experience has been rendered meaningless? What is identity? The questions are especially pertinent to South Africa, which systematically strips the majority of its population of its manhood. But they pertain to us all.

Although Fugard writes realistically, he is a spiritual kin of Samuel Beckett. Both are dramatic poets, singing the grandeur and misery of man in an inhospitable universe. When Piet tells his fretful wife that the hours are passing slowly because "we're flattering time with too much attention," the line could have come straight from "Waiting for Godot." The sense of claustrophobia, futility, lives washing away like sand castles, is that of Beckett's "Endgame."

Arena's production is starkly set, the Bezuidenhouts' plain bungalow isolated from the neighbors by a chain-link fence and cut off from the heavens by taut electrical wires. Director Douglas Wager shapes each moment fiercely -- faces down each moment, almost -- until it renders its dramatic kernel. The pace is slow, but out of the silence a fine cast wrings truth.

Anderson has a confusing accent, perhaps, but his burly boyishness has never served him better. Piet is too big to be confined in a yard, and when Anderson rearranges the garden furniture for dinner, you sense that he once attacked social inequities with the same brusque vigor. There is real goodness in the performance, and unyielding courage. As his wife, Wines seems cast in finely cracked porcelain, and her ultimate surrender to madness is shattering. And Mokae, without sacrificing the rage of the black man, endows Steve with ringing laughter, the bone-shaking laughter of irony. It is a stunning counterpoint to the material.

"A Lesson From Aloes" never strays from a sorry patch of South African turf. But rigorously, uncompromisingly, it leads an audience to the edge of a chasm. The chasm is the human soul, and its treacherous depths are haunting indeed.

A LESSON FROM ALOES. By Athol Fugard. Directed by Douglas Wager; set, Tony Straiges; costumes, Mary Ann Powell; lighting, William Mintzer; with Stanley Anderson, Halo Wines, Zakes Mokae. At Arena's Kreeger Theater until Dec. 20.