By Scarlett Thomas

Anchor. 358 pp. Paperback, $13

Many are the coy fictions that confine readers' pleasures to allusions and wordplay borrowed from earlier classics. Recent such experiments include Lisa Dierbeck's "One Pill Makes You Smaller," a labored 1970s take on Lewis Carroll's "Alice's Adventures in Wonderland"; Katharine Weber's claustrophobic contemporary exercise in Louisa May Alcott-spotting, "The Little Women"; and chick-lit appropriations of Jane Austen far too numerous to mention.

For some reason, L. Frank Baum's "The Wizard of Oz" has been the most successful wing of this pomo appropriations industry, perhaps because it's already best known to most of us in its adapted movie form. Geoff Ryman's novel "Was" shaped some Oz-themed materials into a bleak, multilayered parable of family dysfunction; Gregory Maguire's "Wicked" famously retold the Oz saga from the viewpoint of the Wicked Witch of the West. One would think that these strong outings would pretty much tap out the Oz vein for serious novelists. But Scarlett Thomas's exuberant, heartfelt debut novel, "Going Out," manages to extend the franchise successfully.

Thomas adopts the washed-out English burg of Essex as a stand-in for Dorothy's Kansas, and a New Age healer holed up in a Welsh Travelodge serves as the wizard. There are also a pair of witches and a surrogate Tin Woodman and Cowardly Lion -- indeed, Thomas's protagonist, a twenty-something waitress named Julie, is more Lion than Dorothy.

But Thomas plainly understands that a novel is not a scorecard; the proceedings in "Going Out" don't merely retrofit characters from Baum's classic into rain-drenched, bitter British form. Rather, just as the original Oz saga spoke to widespread anxieties over embattled rural virtues in a rapidly industrializing America, Thomas nimbly reimagines her version of Oz as a meditation on the inward dimension of the Oz quest: the restless, oft-thwarted striving after true feeling in a world of strategic self-protection and blank media saturation.

At the center of the quest is 25-year-old Luke Gale, who has been diagnosed with a rare syndrome known as XP, which makes him highly allergic to sunlight. The last time he was outdoors, some 16 years before, he darted onto his front lawn and nearly died. Now Luke stays in his room, watching copious amounts of TV and becoming immersed in that great surrogate world of experience populated by all varieties of domestically confined souls, the Internet.

Yet Luke is growing restive, stuck behind four walls under the watchful supervision of his panicky mother, Jean, and hanging out with his best friend, a neighbor named Julie, who has her own difficulties encountering the wider world. She ditched her extensive high school math studies and the prospect of a generous college scholarship, deliberately failing her A-level exams so she could work in one of Essex's countless interchangeable chain restaurants (a poorly managed and often-closed pizza concern called the Edge). She tells herself she sabotaged herself so as to continue looking after Luke, but in reality she's developing a series of morbid fears about everyday interactions -- riding trains, traveling on freeways, eating anything but the most antiseptically prefab kinds of food -- that amount to a creeping agoraphobia. In addition, she privately regards her choreographed failure as a small, faintly heroic act of resistance to the encroaching numb expectations of adulthood: "Each time Julie failed another exam, she walked out of the exam room defiant, rebellious. . . . She sank into [her failure] like a huge blanket, comforting and secure."

Once Luke begins trading e-mails with an Asian healer named Wei, however, both friends are on course to be rudely jolted out of their carefully insulated routines. As Luke discusses the prospects for a healing session with Wei, Julie abruptly quits her slacker waitressing job. Meanwhile, a number of other misfits get drawn into Luke and Julie's general orbit, and a full slacker company of a half-dozen careworn souls end up shepherding Luke to an appointment with Wei in Wales. They wrap up the sunlight-sensitive patient in a homemade spaceman suit insulated with -- yes -- tin. This being a dreary English city, however, nothing so calamitous as a tornado sets the crew in motion: They set out, rather, under cover of weeks-long rainstorms and rampant flooding. The jittery Julie is the only one of their number who can drive, but fearful of motorway speeds, she insists on taking a meandering network of back roads, all represented on their map in -- yes -- yellow.

Much like Julie, Thomas manages to keep the proceedings on a surprisingly even course through a number of less-than-plausible twists and switchbacks. She succeeds mainly because of her close attention to character and dialogue, all too scarce commodities in the spare minimalist world of so much contemporary fiction. In Luke, for example, she takes the voyeuristic TV-movie conceit of the freakish boy in the plastic bubble and effectively inverts it, making his condition speak to more universal and free-floating impulses familiar to all of us in an age of undemanding entertainment and emotional retreat. "Sometimes I worry that even if I did get out of here," he tells Julie, "I wouldn't be able to follow what was going on because . . . it would be like someone who knew how to sit in a garden thinking that meant they could trek through a jungle or something. Maybe I can only understand things through stories, and I can only understand characters on TV -- not real people, and I'm better off staying in here with my TV because of that." Likewise, Julie's over-rationalized phobias come off as a natural extension of her attraction to mathematical certainties: "The more Julie simplified her life, and the more logical and safe it all seemed, the more distance she seemed to put between herself and the rest of the world."

It gives nothing important away to note that in Thomas's world, as in Oz, the magic healer is able to turn these frailties into saving strengths. Or that Luke's initiation into the uninsulated world turns up some worthy homilies for the rest of us. Baum's final moral, of course, was that your heart's desire was in your own back yard; Thomas has adapted that sage counsel to an age when back yards themselves can be terribly hard to track down.