The vital signs of "Other Halves" would lead you to believe that the novel is hot enough to make a sunburned Valley Girl blush. The cover copy makes the usual modest claims for a torrid romance: "When all the taboos are broken, only the most extraordinary love can survive." Forget the taboos, cliche's make the going rough enough for this odd couple.

Against the trendy background of New Zealand's beach communes and upscale suburbs, Liz, a 33-year-old white housewife, falls madly in love with Tug, a sexy 16-year-old delinquent. He also happens to be a Maori, one of the outcast aborigines crowding into Auckland.

This is rich, uncharted material for a first novel, but New Zealand journalist Sue McCauley whitewashes it with sermons on "how the other half lives." "Other Halves" reduces passion to a sociological striptease that bares liberal angst.

The affair between Liz and Tug begins as friendship at Valleyview, a mental hospital. Liz has faked a suicide attempt to get admitted. The ruse is a last resort to escape her husband, whose attitude toward emotional commitment is "that sex should be an accepted alternative to the handshake." For several years, he has refused to speak of the death of their daughter because there is no "reason" to talk about it.

At Valleyview Tug swaggers with contempt for the hospital inmates and their middle-class anxieties. (He has conned his way in to evade a burglary charge.) After his release, Tug returns to his "home" on the street. When Liz finds him in a flophouse, Tug's hip scornfulness falters in the face of her motherly concern. Liz, now separated from her husband and child, invites him to her apartment, later to her bed.

McCauley then focuses the novel almost exclusively on Liz's romantic squeamishness about "breaking all the taboos" with a Maori. Liz volleys between guilt and delight at seducing the younger man. Tug's high-spirited sexual prowess reminds Liz of paradisiacal, presettlement New Zealand -- while his illiteracy and vagrancy bring home to her the issue of white colonists' guilt.

It would be nice to have a few familiar coordinates as McCauley charts this reckless obsession. Are Tug's ignorance and cunning a deliciously degrading native aphrodisiac or a legitimate social cause for Liz?

In the tedious role of the Maori advocate, Liz defers this question. As Tug's legal guardian and advocate in his frequent court appearances, she champions his cause by railing against anti-Maori discrimination. Finally she agrees (with misgivings) to house Tug's equally underprivileged and unscrupulous mates under her roof. Despite Liz's social penance, "Other Halves" hasn't nearly as much to say about passion and class taboo as that classy romance, "Lady Chatterly's Lover."

The characters in this short novel are so intriguing, it's a shame McCauley smoothes over their differences with Liz's sappy, gratuitous guilt. For example, Liz wonders whether the affair has made her "just the same" as her leering wiseacre boss Irwin, "except that his fantasy has become my reality."

Tug is a wonderful character, protean, exuberant and foulmouthed. If we knew his resourcefulness helped him survive on the street, or learned more about his perspective on Liz, he might seem less like a caricatured Artful Dodger.

Furthermore, we never learn how Liz finally comes to feel about the death of her daughter, and the disapproval of her son. En route from high-class to low-class communes, she just strings along her obligations as a mother on disjointed memories and custody visits. Her first task is to find a place where she and Tug can be accepted.

Though McCauley's novel was first published in 1982, it's set in the early '70s. Unfortunately, the limitations of her perspective recall the zombie confessionalism of the era. After "Other Halves" has divulged the whole agonizing truth about New Zealand's caste bias, we still feel we're left with a tale half told.