Down Underworld : THE LAST MAGICIAN, <i> By Janette Turner Hospital (Henry Holt: $22.95; 309 pp.)</i>

To get to the Australian rain forest from downtown Brisbane, you take Ann Street, go right on George to Roma Street, and follow the northwest artery as it successively becomes Kelvin Grove Road, Enoggera Road and Samford Road. After an hour or so, “you will cross that indistinct and provisional line where the city of Greater Brisbane could perhaps be said to end, and primordial time could be said to begin.”

Thus, in this opening passage of her Gothic mystery-tale of contemporary evil, Janette Turner Hospital connects the matter-of-fact everyday world with the realm of the mythic. It is as if “The Divine Comedy” started by listing the bus transfers Dante had to make to reach the middle of his life’s road and the dark wood where he begins his visit to Hell.

“The Last Magician” refers to Dante repeatedly. In the swirling montage of images that make up its first part and color the more coherent narrative that eventually emerges, there is the recurring vision of a vortex of damnation. There are references to an old engraved illustration of the descending circles in the Inferno, and to a recent photograph of a Brazilian gold mine where the brutalized workers struggle on swaying ladders from one level to the next. Throughout, there is the central symbol of the Quarry: a metastasizing underworld of wretchedness--part realistic and part allegorical--that Hospital sets in catacombs below the sunny prosperity of Sydney, where much of the action takes place.

The author writes in a densely mannered style, and often with powerful beauty. We need the beauty because, for a long time, very little is clear. Lucy, the narrator, collapses in a London cinema when she sees an art film made by Charlie, whom she knew several years earlier in Sydney, and who suddenly disappeared. There were other disappearances, that of Lucy’s lover Gabriel among them. Certain shots in the film rip open a scar of tormented memories and, beyond that, a seam of mystery and evil that goes back two generations. Lucy flies immediately to Sydney to take up the quest--the one halted by Charlie’s and Gabriel’s disappearance.

At first we get scrambled fragments of story and characters. There is a pervading sense of universal sickness, a piercing note of denunciation, and striking images that seem to know their places but refuse to reveal them to us. It is as if Hospital were running her own film in fast-rewind, showing everything on the screen but allowing it no pattern. The rewind is not fast enough; it takes nearly 150 pages, and by that time, a reader’s intention to seek may succumb to the author’s intention to hide.

What has been hidden and hinted at so demandingly, though, emerges as a story of high tension and terrifying allure. It begins as dangerous games among five children on a farm outside Brisbane 40 years ago. One of the boys, Robby Gray, is rich and cowardly; one of the girls, Cat, is dirt-poor and fearless. There is Cat’s little brother, Willy, who is slow-witted and whom she fiercely protects. The other two--Catherine and Charlie--are willing captives to Cat’s untamed vitality.

So is Robby, but in a sick and twisted fashion. By birth and family position, he should be king of the mountain, but he is scared of mountains. He loves Cat as the others do, but to him, love means power and possession. In a loathsome and brutal way, he exercises his power, and the innocent Willy is accidentally killed as a result. When the authorities act, Robby’s family standing shields him, and Cat is sent to reform school. Her wild spirit labels her incorrigible, and pushes her to repeated efforts to escape. Finally, it leads her to take to the streets as a prostitute; to disappear--in the book’s thematic image--into the Quarry.

Robby grows up to become Robertson Gray; sleek, assured, a judge, and a powerful member of the Establishment in Sydney. Catherine and Charlie, haunted by the memory of Cat and of what was done to her, grow up trying to come to terms with what they know. They become lovers, then split up and go abroad. She returns from London after a few years and becomes a prominent TV interviewer. He stays in New York as a photographer. Photography provides “The Last Magician” with one of its major themes and with the engine of its plot. The ability of the camera to catch what even the photographer doesn’t know is there--”to let me see what I have seen,” as Charlie puts it--instill in him the conviction that he can recover the past and bring Gray to account.

Charlie returns to Sydney in the late 1980s, 25 years after he left it. His quest is soon joined by Gabriel, Gray’s estranged son. Lucy, Gabriel’s lover, becomes their witness and the book’s narrator. The quest is for Cat--there are some shadowy suggestions that she may be working the Sydney underworld--but it becomes something much broader.

Hospital’s theme is corruption; specifically, the corruption of power. It is a power that, under the pretext of order and social necessity, maintains itself comfortably on top of a cesspool. When necessary, it will use any violent means to secure itself. Gray personifies the corruption as he has since childhood. He is on top and Cat is in the Quarry.

Or, as it turns out, not. Before the book ends, in a pattern suggesting the downward spirals of Dantean Hell, we read of other crimes. When Gray is in his 30s, Cat gets on a trolley car he is riding with his first wife and little Gabriel. That night, Gray comes home all bloody; the next day, he leaves his wife. Years later, the bones of a young woman, scored by stab marks, are found wedged under a rock in the rapids where Gray, Cat and the others once played. Charlie’s and Gabriel’s disappearance follows warnings that prominent people in Sydney want them to stop their quest. And when Lucy, who had fled, returns to Sydney to take up this quest once more, she finds a photograph that seems to link Gray to the vanishings.

Hospital wields her story and characters with the larger-than-life bravura of an Expressionist allegory. Everything is deliberately too much. Both Gabriel and Lucy represent a younger generation determined to breach the gulf between privilege and the Quarry. Gabriel--not very convincingly--has become a muckraking investigator of his father’s world even before Charlie conveniently finds him. Lucy, even less convincingly, was a brilliant student, and when Charlie meets her, she is having a postgraduate cultural and social experience by working in a high-society brothel. She mixes raunchy street talk with quotations from Milton.

Gray is loathsome all the way through. Even his cuff links and the way he eats oysters at fashionable dinner parties are loathsome. His third wife--a deconstructionist feminist who is mean to the hired help; I expect Hospital is settling scores--matches him.

Hospital’s magnifications and simplifications can be jarring, even silly, particularly before we get some hold on the outsized story her outsized methods are revealing. Yet even at her most arbitrary, the author is never careless or coarse. Her writing has perfect pitch; at its wildest, it retains a golden refinement. So do her themes, for all their odd twists. She takes many risks and most of them work; the one that doesn’t is our long wandering through the dark wood of her initial montage, and the long time it may take us before we can trust her there. Good she is, but she’s not Virgil.