In "The Rape of Shavi," Buchi Emecheta attempts one of the most difficult of tasks: that of integrating the requirements of contemporary, realistic fiction with the narrative traditions of myth and folklore. Her novel's theme is a familiar one, that of an unspoiled culture coming into contact with, and eventually becoming corrupted by, representatives of a more "sophisticated" society. The story is as old as that of the Garden of Eden and as new as such "anthropological" science fiction novels as Ursula Le Guin's "The Word for World Is Forest."

In this incarnation we have the imaginary African city-state of Shavi, ruled over by the extremely tradition-conscious King Patayon, "indulgently called 'the Slow One' by his subjects." The novel opens with a scene of casual court intrigue: The Queen Mother, slightly miffed at the king's intention to remarry without propitiating her with a cow, has come to wreak havoc at the king's assembly.

At first it all seems to have the feel of an Austenesque comedy of manners, bizarrely transposed to another culture. Then things suddenly take a more catastrophic turn as a great bird of fire falls from the sky and disgorges some creatures -- hideous albinos who don't seem to understand the simplest realities of proper social conduct. The new arrivals become the subject of heated debate: Are they human? Have they been sent by the goddess at the request of the Queen Mother to torment and confuse the king?

These visitors are, of course, all too human. They are Europeans in flight from the threat of nuclear war, and their plane has crashed. Some react to the villagers' hospitality with bigotry; others embrace it. But perhaps the most interesting aspect of this novel is that, while the natives of Shavi are portrayed as complex individuals, the representatives of Western civilization are shown, more or less, as two-dimensional, mythic types. It's a point of view rarely expressed in novels of this kind, and particularly welcome here.

A novel that examines an "innocent" society's fall from grace could easily become polemical or maudlin. Emecheta avoids these pitfalls. Her paradisaical Shavi is shown to have its dark side, as the women of the kingdom band together to exact a hideous revenge of a rapist and hide all traces of his punishment.

There's the high priest, who vainly attempts to contort reality into an uneasy reconciliation with the labyrinthine logic processes of the kingdom's bird-worshiping religion. And, most confusingly of all, there is the brilliant, doomed crown prince Asogba, who, enticed by the visitors' exciting new ideas, stows away to England in their jerry-rigged airplane only to be jailed by Immigration, and who returns to the village of his birth to instigate the reforms that will bring about the novel's tragicomic conclusion. His is a fascinating portrait of an intelligent, ambitious young man whose psyche has been shaped by cultural forces staggeringly alien from our own.

The central thesis of "The Rape of Shavi" is brilliantly, relentlessly argued, and Emecheta's characters and societies are depicted with a bittersweet, sometimes painful honesty. Yet it finally is her prose that is most persuasive. It is prose that appears unusually simple at first, for it is full of the kind of rhythms and sentence structures more often found in folk tales than in contemporary novels.

Indeed, in electing to tell her multilayered and often very contemporary story within a highly mythic narrative framework, the author walks a fine line between the pitfalls of preciosity and pretentiousness. By and large, the tightrope act is a success. Emecheta's deceptively simple language conceals the convolutions of Shavi's society in all its idyllic bliss and hideous superstition, its abjectness and its richness. It's a compelling achievement . . . both dreamlike and horrifyingly real.

And at the end of the novel, when Emecheta finally asks the most important question: "Viyon, what exactly is civilisation?" the ambiguous answer provided ("It is difficult to say") is the only one that can be expected. But on the way to that preordained conclusion, she has given us a vivid novel, biting, poignant and compassionate.