Children of Light by Robert Stone (Knopf: $17.95; 258 pp.)

Gordon Walker writes florid movie scripts and acts King Lear on the stage. He belongs to the Southern California beautiful-and-damned set. His life is a mess, his children are a mess, his wife has left, and he is off to Baja California to look up Lee Verger, a former beautiful-and-damned playmate, who is starring in a film based on one of his scripts.

But every time Gordon does something emotional, he needs to stop for a hamburger. Before he makes love: a hamburger. Afterwards: a hamburger. When he sets out for Baja: a hamburger. When he spots Lee, wreathed in glory and hallucinations: a hamburger. When he trails her on a final unhinged adventure, he ducks inside for: still another hamburger.

Well, of course it’s not hamburgers. “Children of Light� takes very expensive people at their own level of self-indulgence. So it’s cocaine and alcohol. But it might as well be hamburgers. This painfully bombastic novel is very largely about what people ingest and how it makes them feel. Gordon is a bottle. Filled with white powder, he turns white. Whiteness is his romantic agony.

Stone, as he showed in “Dog Soldiers� and “A Flag at Sunrise,� is a writer of considerable force. He can lay out death, particularly death of the soul, in a couple of lines. He is all high-tension wires; and here too.

But in the other books, he was dealing with large subjects. His characters were defined more by their taut and twisting emotions than by their natures, but we heard them even if we didn’t especially feel them.

“Children of Light�--its title announces its ambition--aims to be a searing portrait of decadence. But for the “damned� to matter, the “beautiful� must matter too. Neither Gordon, nor the alluring and demented Lee, whose real name is Lu Anne, nor the whole squalid pack of film makers amounts to very much.

For Gordon, living on the point of crack-up, the trip to Baja is a pilgrimage of a sort. His agent, who represents reality--Gordon doesn’t seem to have friends--wants him to straighten up, dry out, and take steady jobs to hold himself together. Clearly, he is heading into danger. He is trying to re-create the druggy exaltation of his younger days in the company of an old lover who herself is on the fringe of madness.

The agent argues with Gordon, and the agent’s young assistant sleeps with him; but to no avail. He will have his last fling, though he takes the precaution of stopping at a doctor’s to get some downers to offset the cocaine/alcohol cycle. Alice-like, nibbling alternately on the growing and shrinking sides of his mushroom, Gordon advances into wonderland.

It is a despicable place, populated by Nathanael West locusts. In its isolation, its artificiality, and its self-absorption, a film location is both a convenient and a well-worn way to symbolize a decaying and alienated society. The collection of monsters that Gordon encounters are all too familiar. There is Drogue, a talented but corrupt director, and Drogue’s father, a goatish and cynical man who was once a celebrated director himself. There is a revolting journalist, a demented PR man who tries to blackmail the production, a shadowy producer with mysterious money behind him, a blank and sexy starlet.

They work, drink, snort, scheme and quarrel. Stone is very skillful at suggesting the murderous tensions and pressures among the company. Outside, of course, lies Mexico; rather like Malcolm Lowry’s volcanoes, and with a similar estranging effect.

In this murky aquarium, Gordon and Lu Anne are the shiny and poisoned fish. A radiant product of the Yale Drama School, she, like Gordon, has been through the twin burnouts of chemicals and fantasies gone bad. Her burnout is worse, though; she is attended by imaginary creatures with lacy wings whom she calls her Long Friends. They make her scream suddenly, or mistake the figure on a crucifix for a martyred cat.

Lu Anne, nearing 40, sees in the film she is making a last chance to save herself. She refuses the medication prescribed to hold madness down, because she wants to shine. As old Drogue puts it: “She has a way of being crazy that photographs pretty well.� Clearly, her last chance will be her death warrant.

She and Gordon withdraw into each other for days of drugs, sex and hallucinations. Finally, Lu Anne snaps. She hauls Gordon out to climb a mountain. On top, in a thunderstorm, she strips, daubs herself with mud, and lacerates herself with flints. The couple end up pelting each other with pig manure. Other things happen afterwards, but this is the book’s climax; it’s a blithering one.

Stone, who had managed some tight writing, dissolves along with his characters. The mountain is called Mount Carmel, and the whole episode, self-inflicted stigmata and all, becomes a hokey mystical vision. The dialogue is a ludicrous melange of the hip and the holy. Here is a bit, on the way up; starting with Gordon:

“ ‘There’s to and fro. There’s back and forth. There’s up. Likewise down. There’s taking care of your feet.�

“ ‘And the small rain,’ Lu Anne said.

“ ‘And mud. And gravel and sand. And shit. And wet rot and dry rot. And going over fences.’

“ ‘Can you look back?’

“ ‘Never back. You can look down. You have to see where you’re going.’

“ ‘But is there a place for art?’ Lu Anne asked with a troubled frown.�

Not really. Stone’s efforts to make a touching and sardonic parable out of Gordon, Lu Anne and their bottles amount to a classical definition of melodrama; the application of grand emotions to trivial subjects.