Willie Croft is a 42-year-old jailhouse lawyer from a southern Louisiana port town called Bienville. Willie drives an 8-year-old Nash convertible, has been on an airplane only once -- in the Army -- and has never experienced oral sex. In the course of Winston Groom's new novel, "As Summers Die," Willie gets rich, keeps his Nash, doesn't fly but learns the joys of oral sex. A couple of steps up from poor white trash, Willie is a true naif, with no head for paranoia or three-story conspiracies. "All his life," the book tells us, "Willie had lived by a simple homespun honesty. He had worked hard, learned his law and had a certain assurance in the way he applied his craft, such as it was. Nothing fancy."

Willie Croft clearly is in for a few surprises.

"As Summers Die" is a what-if book: What if in 1959 oil were discovered in a chalky old piece of property in southern Louisiana, a piece of property so without value that its owners, the Holt family, have over the years sold most of it off and what they have kept have left in the hands of poor black vegetable farmers. The Holts are Bienville's leading family. The property, "a harsh, unyielding place," has come to be known as Creoletown.

Now what if, one day in November of 1959, before the "infamous Stand in the Schoolhouse Door, the Voting Rights Act and Public Accommodations laws, the Selma March or the Battle of Ole Miss," the Holts' lawyer were to inform the family that "Creoletown and its environs were possibly sitting atop the largest oil and natural gas field since the famous Spindletop discovery near Beaumont, Texas, in 1901." And what if on the other side of town Willie Croft's maid Priscilla were to come to him to ask his advice on the matter of her mother's Creoletown property for which a Holt brother had first come to offer "$25,000 in hard cash," and then an oil company representative had come to ask about mineral rights. Priscilla's mother, Mrs. Elvira Backus, has refused both offers. And what if Willie Croft out of curiosity were to go out to talk to Mrs. Backus and find her in her home, holding onto a deed signed by a Holt one-generation deceased, a man who is father not only to the very Holts seeking to disallow the old woman's claim, but of mrs. Backus' children as well. Priscilla is a Holt, as is her brother, and Holts are Bienville's leading family. Miscegenation: The white Holts are horrified.

Once the what-ifs are set, "As Summers Die" moves smoothly, if predictably. When, for instance, early in the book, Willie Croft meets Whitsey Loftin, a cousin by marriage to the Holts, and finds her suddenly more attractive than he had remembered, their becoming romantically involved is as sure to follow as the next page. Whitsey's attraction to Willie, we understand, will both set our unaccustomed hero up for trouble as well as provide him some otherwise unattainable family secrets.

In the front of "As Summers Die" there is a quotation from "Alice in Wonderland" ending, "Life, what is it but a dream?" And another from Ecclesiastes, the familiar, "time and chance happeneth to them all." Groom is clear, then, what he is about. His what-if is wistful, dreamy, a fancy. What if, he is saying, this happened in the South in 1959 before the real struggle started and what if it worked? What if the black people won? Even in one small south Louisiana town? (Groom has chosen his setting wisely; only in that particular section of that particular state, where race is a hazier fact and distinctions less clear, would such a premise be even remotely plausible. Northern Louisiana would not do, at all.)

Willie Croft defends Mrs. Backus' rights to her property. With the assistance of other monied black people, including some Muslims from Chicago, he wins her a clear title, then helps the entire group put together its own drilling company, the Obsidian Oil Corporation. It works. Oil comes in. The money in Bienville gets redistributed. Things change. Together, blacks and whites attend the grand opening of a downtown Cajun restaurant financed by the Obsidian Oil Corporation. Not all the white, not all the blacks. Still . . . some of each. A dream.

The best parts of the book are the hunting and fishing scenes, in which Willie goes to his father's cabin and with an old guide maneuvers through the marshes, reminiscing as he goes. Here, Winston Groom explores the memory of the senses, nostalgia. The book comes alive in these pages. Groom's ear tunes up and finally, the language sings.

The premise of "As Summers Die" -- particularly regarding the effect of redistribution of wealth, crossing over racial lines -- is of interest. The book should have been better. Groom has the ability, as is evident in his first book, "Better Times Than These." He has picked the right setting and he presents us with some energetically drawn characters, all of whom are passionately involved. But the plot feels rigged. The "then-what?" following his "what-if?" strains persuasion to the point that disbelief defies suspension. It is as if the author had fugured the angles in advance, then reshaped them as necessary to fit the story he was dead set on imagining. No surprises.