Sightings by Susan Trott (Simon & Schuster: $16.95; 224 pp.)

There is betrayal, madness and murder in this novel. And in the course of it, the author goes so far as to compare her story to classic Greek drama. As if that clears her to get on with the book’s better half--its characters.

The heroine, Sunny, is a young, California goddess with shimmering blond hair and the sturdy physique of an athlete. Her father, Muir, sends her off to Paris for a high school graduation present.

She falls in love with Masefield, a Rhodes Scholar, a rookie spy, and a friend of Muir, he says, though it is never quite clear how the two men know one another.

At the local cafe, Aux Deux Magots, Masefield and Sunny meet Ernest Hemingway, which proves to be a disorienting scene. His presence implies that the setting is the past, though everything else about the story and the people in it suggests the present. Hemingway’s role would also seem to give him a stake in this story’s future. But the cafe scene turns out to be his last.

Trott throws other false leads in our path besides. But this one, in particular, is unsatisfying. She parodies the tough-guy’s prose style after he makes his exit, but that seems to be her best excuse for dragging him bodily into the act. It doesn’t seem reason enough.

Back home, near San Francisco, Sunny’s father has run off with her best friend who is about to have a baby--presumably his. And her mother has lost her senses and set sail in search of Andy, Sunny’s brother, who drowned years ago.

Only her longstanding boyfriend, Buster, seems to be his usual self when Sunny gets home. He’s dumb, but he’s dependable. She tells him she’s in love with someone else who promised to join her soon, and for a time it looks as if Buster is about to lose his reputation. But he pulls himself together and proves to be a selfless friend, taking care of Sunny until her true love arrives.

That takes five years. By then Sunny has a baby--she got pregnant in Paris--and names him after Masefield. But it’s Buster who raises the boy. By the time Masefield and Muir reassemble around Sunny there is every reason to consider them a classic pair of ingrates. But what seems to be the book’s message blares through the story’s last scenes: Nobody is the person they first appeared to be. Not Masefield with his seemingly casual concern for Sunny. Not Muir who abandoned his poor wife. Not even Buster, who was raised an orphan but might not be one after all. (In the end, only the author knows for sure.)

Trott’s easy prose style, her effective use of multiple narrators and her crystalline study of Sunny as the sexy, sweet-hearted jock, are impressive. For that much, the book deserves a place in a well-stocked summer beach bag.

But the twists she builds into her story are done with a heavy hand that leaves too many rough edges. The final episode with its all-too-tidy break-up of the Buster-Sunny-Masefield triangle is hard to settle for. And the murky motives, not to mention ethics, of her characters make it difficult to put an abiding faith in Susan Trott’s “Sightings.”