SAVAGES By Shirley Conran Simon and Schuster. 587 pp. $19.95

YOU SORT OF want to like Shirley Conran for taking what counts, in the context of bestselling fiction, as a creative risk. It's refreshing to see a leading shlockmeistress, author of the frothy 1982 hit, Lace, write a book set somewhere other than in the capitals of Europe, with heroines who have concerns more immediate than shopping and marrying up. And few enough people write out-and-out adventure novels for women that it would be nice to praise Savages as a welcome departure from the Concorde-and-caviar set.

But then again. Fish gotta swim, birds gotta fly and Shirley Conran gotta write camp.

Perhaps not since Jaws has there been a novel so high-concept, susceptible to summary by sentence fragment, as this one. If Conran were a different sort of writer, you might say that Savages was the adventures of Robinson Crusoe as undergone by Mary McCarthy's Group. Because Shirley Conran is who she is, it is more accurate to say that her new effort is Gilligan's Island as it might be rendered by Rona Jaffe.

In the realm of popular fiction, a high concept does not mean a bad concept, and you have to credit Conran with a fine set-up. The executives of a Pittsburgh mining company set out with their spouses for a corporate "retreat" on an island off Papua New Guinea. (For maximum friction between her characters, Conran arranges that the trip take place on the eve of the chairman's designation of a successor.) Through an ingenious combination of corporate hugger-mugger, mechanical breakdown and indigenous revolt, Conran isolates her five heroines -- all pampered corporate wives -- in a jungle otherwise occupied mostly by cannibals. Their mission is, of course, to escape in one piece. Their misfortune in the meantime is (in the words of the advertising copy) to "find themselves confronting the most dangerous threat of all -- for their own exposed and violent passions have turned them, far more than the predators they are fleeing, into savages . . . ."

Before too long, Conran is threatening to reprise with a minor change of verb the most famous line from Lace: "Which one of you bitches ate my mother?"

Conran has done her homework as thoroughly as ever, simply switching her traffic in telling detail from couturiers and cafe's to poisonous vegetation and jungle fauna. She bandies survival tricks and forest lore about with impressive ingenuity.

Nor do the novel's problems lie in the characters. They are not a whit more animated than the engineering of commercial fiction demands, but they're not bad little engines, as engines go. Suzy is the misunderstood bombshell who drives all of the others nuts until she is both strengthened and softened by adversity; Carey is a Nordic amazon who has a career in her own right; Patty is a compulsive jogger and the guilt-ridden mother of a son born with spina bifida; Silvana is the depressed wife of the uncaring company head; and Annie, mother to four hulking sons, is the martyred wife of an executive named Duke.

THE PROBLEM is that the story gets away from its author, and the book's pretensions become the tail that wags the shaggy dog. The author appears to have set out to say something serious about the influence of stress on character and about how women relate to one another. (Do not take a reviewer's word for this. Simply note that most commercial novelists lack the nerve to choose epigraphs like the one that introduces Savages: "To do is to be -- John Stuart Mill.") But as she speechifies and summarizes on the themes of group behavior and self-reliance and mutual trust, she is passing up chance after chance at drama. Even where she troubles to create enriching subplots, she almost always fails to resolve them.

Two of the women develop a sexual rivalry over a third, but never reach any confrontation or conclusion over what they consider their own shameful behavior. While each of the women grows more competent with every swing of the machete, none seems to achieve any kind of epiphany about her newfound survival skills, and we never learn how they will live later with some of the desperate things they're forced to do.

The problem also lies in Conran's writing. While one hand is working mightily to make you like and respect these women, the other hand is busily undoing that work by making them "sob" and especially "snuffle" a lot and by keeping a sort of prurient watch on the changes in their appearance -- who is the last to convert her bra into a sling shot, and how fast Suzy's brown hair outgrows her blond dye job.

Savages shows that you can take the prose out of the purple, but you cannot take the purple out of the prose. "The brutal wind lashed their faces, tore their breath away and sucked the warmth from their bones. Howling with rage, it tore at their battered bodies and froze their flesh," runs a fairly typical example of Conran-as-naturalist. The author also seems unaware of the comic aspects of even her most workaday prose: "Gratefully, the women hurried along . . . , faster and faster, until their stealthy jungle lope developed into a run, then into a mad, headlong hurtling. Careless of who or what they might encounter on the track, all jungle lore forgotten in their panic, they crashed along as fast as they could."

In the end, Savages is not unlike a trek through the jungle, if not always at such a breakneck pace. You put one foot wearily in front of the other, you beat back a lot of undergrowth, and after hours and hours you're apt to find yourself right where you started.

Perhaps, after all, it's a cross between Deliverance and The Women.

Marjorie Williams is a staff writer for the Style section of The Washington Post.