I never thought I'd want to know more about the life and times of Danielle Steel. But having screened tonight's NBC-TV movie "Once in a Lifetime" and dipped into the novel it's based on, I admit that I do. Daphne Fields, Steel's presumably autobiographical heroine, is so decisively a creature of melodrama that it's hard to imagine anyone's real life providing the model for her. But that, of course, is Daphne's appeal and the popular pull of Steel's fiction: the perfect arc from loss and suffering through self-help to lonely sufficiency, then on to success, riches, fame and true love.

The record does show that Steel is probably the world's best-selling and richest living writer, with 31 books of fiction and poetry to her credit and an annual income estimated at $25 million. Tonight's "Once in a Lifetime" (9 p.m., Channel 4) is Steel's flattering vision of herself filtered through her usual fictional contrivances.

Costarring Lindsay Wagner as Daphne and Barry Bostwick as the graying hunk she loves without really acknowledging it until the final frames, the telemovie is implausible, impossibly sentimental -- and good tear-jerking fun.

The plot is a smoothly predictable chain of Steel events. After the required tragedy, in which Daphne loses her beloved young daughter and husband in a Christmastime house fire, she grows stronger with every narrative link. Never mind that the son she bears months after the fire is deaf; his impairment is less a problem than a whetstone on which to sharpen her devotion, a challenge to her soaring potential. Between mastering sign language and her understandable overmothering, she hunts and pecks at a novel about -- you guessed it, herself.

And so she goes, laboring cheerfully, upwardly toward the stars, which include a handsome actor who briefly sweeps Daphne off her feet and onto a motorcycle. But that comes quite a bit later, when her second novel, I believe, is being made into a Hollywood Western.

"Once in a Lifetime" is TV's squeaky-clean equivalent of the kind of big-screen popcorn romance that has recently become a little too coarse, too lightly blue, for some old-fashioned eyes and ears. It's a pearly string of cliches lubricated with soap, the saga of single woman winning against the odds without benefit of any explicit appeal to feminism.

It's hard to imagine that almost any of this would be said had not Lindsay Wagner been cast as Daphne. Her projection of strength combined with sharp intelligence, along with her untypically seasoned prettiness are not qualities you expect to get in this sort of small-screen extravaganza. Wagner is gifted enough to evoke an inner life and a spectrum of honest emotion richer than the material deserves.