Foreign Waters : BRAZIL, <i> By John Updike (Alfred A. Knopf: $23; 260 pp.)</i>

In the tropical sun on Rio de Janeiro’s Copacabana “the beach felt blinding.” Down from the hillside slums, Tristao and his half-brother Euclides are on their daily scavenge for purses and other opportunities. The two black youths spot the well-born Isabel, blond and fair-skinned, in her pale bikini. “This dolly, I think she was made for me,” Tristao exclaims.

He takes off a ring inscribed “DAR”--it means give in Portuguese but in fact it was extracted by razor from a visiting blue-rinsed Daughter of the American Revolution--and presents it to Isabel “because you are beautiful and, what is rarer, not ashamed of your beauty.” Instead of uttering the Portuguese equivalent of “eek!,” Isabel comes back equally high-flown. “It is dangerous to be beautiful--that is how women have learned shame,” she tells him. Before long they are off to her uncle’s luxurious apartment so that she can lose her virginity. Tristao soothes her initial nervousness: “My advice is to let yourself sink to the point where my pleasure and yours are the same.”

If it were not for the book-jacket or title-page, a reader would hardly guess that these opening pages of “Brazil” were by John Updike. Their diction is opera in an uncertain translation. Updike’s Massachusetts beaches might dazzle but they would never feel blinding. His sex always has a worm of fleshly itching in it; in this new novel, though far more extravagant and detailed, sex is almost wholly gestural. It makes the earth move while Tristao and Isabel, on the other hand, barely wiggle.

“Brazil” is Updike’s only entirely foreign novel since “The Coup.” It is very foreign indeed; much more than if a Brazilian had written it, since the Brazilian would be writing of his or her own world and, in the case of a great writer--Updike cites Machado de Assis and Clarice Lispector as two of his models--we would feel part of that world. In “Brazil,” despite its moments of charm and several risky accomplishments, we are tourists, unsure about the water and whether the half-caught phrase is an endearment or the offer of a stolen watch.

Updike navigates between romantic fantasy and sardonic allegory in tones that shift from the operatic style of some of the speeches to moments of comic realism. Despite the names of the protagonists, it is not quite “Tristan and Iseult,” although its lovers are, to some extent, star-crossed. As they discover their fates in each other, flee her powerful family’s wrath and adventure across the Brazilian wilderness, their recitatives take a Puccini-like turn; as in “The Girl of the Golden West,” perhaps.

Updike makes the eloping of the young pair a parable for the union of Brazil’s extremes: its vastly rich light-skinned ruling class, and its mixed-race and native South American multitudes. It is quite as stormy and unlikely as such a union would be, with extravagant incident, a touch or two of magic and a dour, ironic ending.

The couple goes first to Sao Paulo to take shelter with Tristao’s brother, who has made his way up from the slums to work in a car factory. Her father, a powerful diplomat who lives in Brasilia, sends a gunman to get her back, under the threat of killing not only Tristao but his family as well. The gunman is an amiable villain, worthy of Graham Greene. “He hoped, when his days as an assassin and an enforcer were over . . . to buy his own limousine and become a tour guide.”

While Tristao stays in Sao Paulo, Isabel spends the next two years at the university under the chilly eye of a father whose kiss was “tinged, like luggage stored in the unheated hold of an airplane, with the extra-terrestrial cold of the stratosphere.” She distracts herself by sleeping with an assortment of fellow-students until Tristao turns up again and they flee into the interior.

They buy a gold-mining claim and spend several years scrabbling in a poverty relieved only by Isabel’s employment in the local brothel, which produces food and two children. When the family gunman tracks them down, they dispose of him and flee into the jungle. Native South Americans make off with the children; they struggle on, starving and near death until they fall prisoner to a crazed band of half-white settlers who keep native South Americans as slaves and believe that Brazil is still ruled by an emperor. Their chief takes Isabel as his third wife and makes Tristao a slave.

Isabel sets out on her own trek to a shaman in the foothills of the Andes; they hit it off, and he grants her wish: to make it possible for Tristao to join the country’s ruling class so they can go home. By long-distance magic he turns Tristao white. Since magic is a zero-sum game, however, Isabel turns black. After further adventures, they make their way back to Brasilia. Isabel’s father is too starchily correct to mention her color, and since Tristao is now white he can be promoted into the upper classes. The years go by comfortably, boringly, depressingly until a mugging claims Tristao as the ironic victim of his new white skin. Isabel’s heart is broken but it goes on beating.

“Brazil” is something of a mess, if at times an interesting one. Updike tries to make Tristao and Isabel both symbols and personages, but the two elements don’t bond very well. We assume that Isabel’s compulsive infidelity and her ability to conceive children with everyone except Tristao says something gloomy about the unbridgeable divisions of the society. She takes the practical lead but worships him like a sexual fetish--so long as he is black and she is white. When the colors are reversed, he more or less takes charge of their lives but his primal energy recedes into a neurotic brooding, while Isabel turns earthy and her erotic adoration gives way to a matter-of-fact raunchiness. Whatever the color, it is class that counts; Isabel will ultimately be the one not to end up as victim.

The symbolic meaning of all this is more or less apparent though faintly distasteful, if only because it has the whiff and presumption of cultural tourism. More seriously it tends to muddy the incipient allure that Tristao and Isabel possess as characters. The book is stronger in Updike’s sense of place than his sense of people. The contrasts between Rio, Sao Paulo and Brasilia are vividly rendered; so are the feel and the sights of a rickety bus journey through the red dirt and derelict towns of the interior. In taking an artistic sensibility abroad, a country is more accessible than its countrymen. Visitors commune more easily with Paris than with Parisians.

The impulse to travel consists, in varying proportions, of the need to leave somewhere and the need to go somewhere. With Rabbit dead, and Updike’s other American themes so thoroughly and finely worked through, “Brazil” may indeed reflect an urge for departure. He has not quite made an arrival.