A woman has been raped. As her assailant prepares for his getaway by binding her hands with a tie and her feet with an alligator belt (he is an executive rapist), she looks up at him and declares with absolute conviction, "I'm going to have your child."

This emotionally implausible opening scene sets the tone for a new novel by Elizabeth Forsythe Hailey, author of the widely acclaimed "A Woman of Independent Means" (1979). Hailey's first novel, which traced the development of a girl born in the late Victorian era into a self-sufficient woman, pulled off the difficult literary feat of revealing character in epistolary form -- a device that, because of the triumph of the telephone and the decline of personal correspondence -- is unsuited to fictional portraits of late 20th-century men and women.

"Life Sentences" is a disappointment not because it fails to resemble Hailey's earlier work -- who would want or expect a writer to produce a second epistolary novel? -- but because it offers no reasonable motivation for the behavior of its characters. In its reliance on coincidence and catastrophe, the novel is scarcely recognizable as the work of the author who wrote "A Woman of Independent Means."

The central character is 42-year-old Lindsay, the rape victim who receives her annunciation as she is being assaulted ("Like a woman in love, she was convinced conception had taken place"). Lindsay has kept a secret for 20 years: She has a husband who was totally paralyzed in a boating accident on their honeymoon, although his mind continues to function. (How she knows his mind functions is never explained, since he cannot speak and his face evinces no emotional response.) Nevertheless, she spends every weeknight with him in the hospital -- which is why she can only see her lover, Todd, on weekends.

Todd, who loves Lindsay and wants to marry her, knows nothing about the husband but has accepted a weekend courtship for 12 years. His reasons for acquiescing to these limitations constitute another mystery. Todd finally learns about Lindsay's husband after the rape, when she informs him she is going to bear the rapist's baby. Is he outraged that she wants to have a rapist's child when she refused to have his? He is upset but not really angry, and his devotion to Lindsay never wavers.

This plot summary encompasses only the bare outlines of the amazing array of disasters that beset Lindsay and those around her.

The characters in this novel are not exactly like one of Joan Didion's neurasthenic heroines, who boasts, "What makes Iago evil? some people ask. I never ask." They do ask questions, but the answers are incomprehensible. Lindsay, for instance, does ask herself why she is unable to loosen the ties to a husband who is beyond her help. She insists on the nightly talks because "for the first time in her life, Lindsay could admit everything and be forgiven." Forgiven for what? Don't ask.

" . . . Lindsay discovered that by putting her thoughts into words for him to hear she understood them better herself. It was an arduous process in the beginning--conducting a monologue -- until she learned to include him. Keeping her eyes firmly fixed on his face, she began to imagine the comments he might make, the objections he could offer. When she started putting his imagined point of view into words too, the monologue became a dialogue."

This passage might work as a study in pathology, but Lindsay is presented as a reasonably normal woman -- troubled, wounded by unpredictable life events, but not all that different from you and me. There is no suggestion that Lindsay might be wildly unbalanced -- that there is something more than a trifle eccentric about a woman whose first response to rape is a profound determination to bear the rapist's child.

In spots, Hailey displays the sharply focused style that made her first novel such a pleasure to read. In one affecting scene, Lindsay begins to see her mother as a woman and not only as her parent. "Watching her mother unselfconsciously remove the brassiere she was buying and turning barebreasted to smile at her as if they were college roommates accustomed to seeing each other in all stages of undress, Lindsay realized with a pang of jealousy that her mother still considered her body a source of pride and pleasure . . . 'You really are a beautiful woman, Mother,' Lindsay said softly."

This was clearly intended to be a story of reconciliation and renewal but the effort fails because the author lays no plausible groundwork for her happy ending. Lindsay and Todd are happy with their child and there is no hint that the manner of the conception could ever be a problem between them.

The deficiencies of this novel cannot be attributed solely to the predictable difficulties of a writer whose first book has aroused extraordinarily high expectations. Hailey's stylistic gifts have not deserted her, but she seems to have been infected by the contempt for causality that has made so many readers forsake serious fiction in favor of romantic sagas that, while lacking the depth and realism of their 19th-century predecessors, at least have the virtue of internal logic. It is the business of genuine artists to make sense of human experience -- or to explain why some experiences make no sense.

"Life Sentences" is about as believable as "Anna Karenina" would be if Tolstoy, after revealing the intractable nature of his heroine's dilemma, had, in the closing chapter, turned Anna into a woman who was capable of packing her bags and getting on the train instead of throwing herself under it.