The plot of this agreeable bit of summer fluff is sufficiently fanciful and implausible so as to strain credulity right past the snapping point, but that is not likely to stop many readers from having a pleasant time with "Flanagan's Run." The novel is an entertainment with few pretensions to being anything more, a book that washes down as smoothly as gin and tonic. Isn't that what "summer reading" is all about?

The story takes place in the United States in 1931, as the full, crushing weight of the Great Depression sinks in on the country. In sharp contrast with the nation's bleak mood, a small-time promoter named Charles C. Flanagan invents and inaugurates "C.C. Flanagan's Great Trans-America Race," in which contestants are challenged to run across the country in daily increments of 50 miles. To the winner will go $150,000 in gold dollars; the total prize money is $360,000, a staggering figure for the day.

The race attracts skepticism, mockery--and, from around the world, some 2,000 runners. A reporter covering the race, commenting on the "motley crew" Flanagan has attracted, describes the contestants:

"His band of 2,000 athletes does, it is true, contain some of the finest long-distance runners in the world. It also contains 121 women, a Hindu fakir, 16 blind men, three men without arms, 20 grandfathers, 61 vegetarians, and a spiritualist who claims to be advised by the long-dead Indian runner, Deerfoot. And this is to say nothing of Madame La Zonga, Fritz the talking mule and a baseball team composed, we are told, entirely of chimpanzees, all of whom are to accompany the runners on their trek to New York."

None of which perturbs C.C. Flanagan in the slightest--all of which, in fact, he welcomes heartily, because "everywhere we go, every minute of the way, I aim to put on a show." It is his hope that the appearance of this caravan in small towns and large from Los Angeles to New York will stir public interest and raise enough money to keep the show on the road. Anything that will help keep things rolling is fine with Flanagan, whether it's a team of chimpanzees or a race between a man and a horse.

The plot, obviously, hangs on several questions: Which runners, if any, will make it all the way across the country? Who will win the $150,000? Will Flanagan be able to keep the Trans-America from dissolving into bankruptcy? Along the way to answering them, Tom McNab tosses into the mix everything from drug-stimulated Nazis to J. Edgar Hoover to Al Capone. He even, in explaining why the long shots run in the race, throws in something that comes dangerously close to being a theme:

"They ran because this was the moment which no landlord, no employer, no politician could take away from them. They had stood in bread lines, taken handouts and pay cuts, watched while plump politicians had pursued their round of conferences. They had watched, impotent. It had not taken them long to realize that others were going to win the Trans-America, nor had it taken them long to reach their personal decisions to continue. They had come to run across America and no one on earth was going to stop them. No, there was no need to ask why these men kept running."

But enough of that. The pleasures of "Flanagan's Run" are to be found in the race to the finish, not in its author's rather primitive political and economic views. McNab focuses on about a half-dozen of the contestants, and the progress of the race is seen through their separate and interwoven stories. They are attractive, interesting people; McNab manages to make the reader care about their fates and to keep them moving swiftly along to the novel's mildly surprising conclusion. McNab is fully capable of writing an intelligent sentence, and he knows whereof he writes: He is a former athlete, a former coach for British Olympic teams and "the script consultant and technical adviser for the hit film 'Chariots of Fire.' " If ever "Flanagan's Run" is turned into a movie, it could be a very good one; meantime, the novel will do just fine.