Isabel Eberstadt's second novel (her first was published in 1958) quickly hints of dark family secrets, suspicious friends and mystery, a tale to be unraveled in modern Paris. But the first pages of a novel, like any first encounter, may mislead; on further acquaintance, Eberstadt's fiction simply perplexes.

Sis Melmore, the widow of an American tycoon, has crossed the Atlantic with maid and chauffeur to meet her daughter, Sarah. Their rendezvous on the Rue de Rivoli is brief and cold. Melmore is called a murderer; Sarah, disoriented, rushes off and immediately bumps into the peculiar Jack Straw, an artist of sorts, who tells her he was "born with a whole lot of powers," including the power to heal. She becomes his guest, or perhaps his captive.

From Sis Melmore's vantage point, her emotionally disturbed daughter has vanished, and possibly been kidnaped; the stage is set for a different kind of pursuit. Drawn into the lengthy search is Melmore's sister, Harriet Milbanke, who describes herself as "the classic old maid," and is; Anna, who belongs to a vaguely ominous political band, and others from the Parisian demimonde. It is also obvious that mother and daughter are about to pursue the past, in particular the events leading up to family tragedy and Sarah's breakdown.

But upon this promising stage, the players too often ramble uncertainly. Melmore follows false trails and Sarah is pestered by the street-smart Maurice Monaco, Straw's roommate. We learn that Sarah's brother died of a drug overdose, and about the destructive relationship between Sarah and her father--there are early clues that Sarah may have killed him. Much of this is recounted in the hesitant cadences of a 60-page conversation between Sis and Harriet. The rest is remembered by Sarah when she is led into a dreamy, hypnotic state by Straw, who would exorcise her "demons."

The point, though, is elusive, as are many points that inhabit the pages. Elegant Sis Melmore, "still treated like a reigning beauty," playing motherly detective from the Crillon, is an appealing, naive protagonist. But Sarah, at times a rather Patty Hearst-like figure, sleeps through much of the book. Straw is baffling. Though he calls himself a "functional illiterate," he speaks a most literary tongue: "It was the inside of the house, you see, that was wondrous. That could keep a child like me in its thrall." Anna sounds as if she learned English from a phrase-book for troublemakers: "First of all, I must ask you again--and I beg you to tell me the truth--have you talked about this matter of your daughter to anyone official?"

I think Eberstadt is telling us about the importance of love--parental love, sibling love, sexual love--as salvation for all "natural victims," who must otherwise stare into Straw's void: "Well, Sarah, did you ever think that maybe we're here all alone? Sarah, for me on this earth, as far as I know, there's just me and God alone. Or sometimes people, well, not even people, just the shadows of people. Maybe they get in the way . . . " Sis Melmore rediscovers love and so, in her way, does the saintly Harriet. Sarah, in her journey from psychiatrists and pills to Straw's spells, changes, too. She "no longer thought of her father as Satan. He was a strong, dangerously destructive man. It was like living with radium."

But these are not new tidings, and these men and women are not very real--it is as if the author keeps painting over them. The arch chapter headings ("Mrs. Melmore Is Herself Surprised," "Miss Milbanke Is Perplexed") suggest a witty detachment that doesn't detach itself. Straw's self-detonating oddball art suggests satire, but Eberstadt's purpose is not satirical. The violent climax is not thrilling.

Eberstadt, who is the daughter of Ogden Nash, writes gracefully: "The tourists did not jostle her, but flowed around her, eyes averted, as if she were a kind of street accident in which they might become involved."

Wrapped around this language, though, are those swaths of dialogue, muffled by persistent quotation marks; and observations that have been observed before: "The trouble with getting older was that it happened so slowly you hardly noticed. One day, in a strange mirror, you thought, who was that old woman in gray, with the sweet expression? . . . And the whole time you were just a girl inside."

The magic of fiction is that it may set out across familiar terrain and arrive at new boundaries. This does not happen in "Natural Victims," no matter that Eberstadt sets down telling sentences and introduces people who ought to intrigue us. In the end, these "victims" are believable only to the extent that we've met them someplace before. When they become more than that--and Eberstadt, to her credit, demands more--we cease to believe in them.