Sweet Mystery of Life : TEMPLES OF DELIGHT<i> By Barbara Trapido (Grove Weidenfeld: $19.95; 311 pp.) </i>

“Jem was a joyful mystery to Alice,” Barbara Trapido’s new novel begins. And this story of two schoolgirls finding and completing their love is joyful and mysterious through and through.

It is not girlie. It is modern and hip and woven well and hides its depth in luxurious folds of humor.

Jem McCrail and Alice Pilling meet as 13-year-olds, when Jem appears midterm during Miss Aldridge’s Silent Reading Hour. To Alice, Jem is imagination, the world.

The daughter of a “man of letters,” Jem is a fabulous bookish smartmouth who already knows her Dante and Ezra Pound and has also seen Mario Lanza in “The Student Prince.” Alice, the spoiled only child in a two-income suburban household is loving and curious and frequently bored. While she has not gotten around to thinking about boys, her new friend says, “I don’t know if you’ve ever really scrutinized (Michelangelo’s) David’s penis but he looks as though he’s just had his pubic hair styled by Vidal Sassoon.” Alice never heard the word penis uttered aloud.

Jem also is a believer, a truly devoted Catholic. And she considers Mozart the greatest gift a girl could give her friend.

They sit together in the music room at school listening to Mozart’s “The Magic Flute.” To Alice, a rationalist, the libretto makes little sense--a dark and horrid child-abductor, Sarastro, is treated as the high priest at the Temple of Wisdom, and Tamino, in search of love and the lost child Pamina, is something of a dunce but nevertheless gets a magic flute and all the help he needs along the way. The good guys win, though some of them don’t seem so good.

Jem laughs at Alice’s misunderstanding of the Temple and foreshadows the tale which will envelop the two of them for the rest of their lives: “It makes sense in a way dreams make sense,” Jem says. “You don’t expect a dream to be ‘consistent,’ do you? But you know that it’s very deeply to do with the nature of your being.”

Jem disappears soon after.

And Alice grows up--observing the death of girlhood neighbor Flora’s father in a tragicomic restaurant scene, then qualifying for university and finding men. She falls in love with Roland, the schoolteacher who calls her “dearest Poppet” and inflicts upon her a make-an-impression trip to Yorkshire, where she is expected to mother-hen four of Roly’s private-school boys (they speak in “jarring little posh voices, dropping anecdotes with regard to their parents’ importance and telling knock-knock jokes in French.”)

The journey ends with Alice driving her beau’s vintage Citroen into a river when her affection for her rescuer, the handyman Matthew Riley, begins. It is not a deep relationship either, but pushes the tale back to Jem.

Trapido’s is not an upper-class-twit British novel. It is modern and fresh and she is as comfortable drawing cutting social portraits of the private-school crowd as she is cutting down the hors d’oeuvre habit of the nouveau riche in the county (anyone for “Tahini Temptation” or a “Kiwi Cocktail Quickie”?). And she has a vibrant way with urban punks. Here, for example, is just a hint of Iona, teen-age daughter of Alice’s Oxford landlord:

“Iona’s dress was a curious hybrid of puff-sleeved milkmaid blouse worn with a studded biker’s jacket, filthy scarlet cheerleader’s skirt and high-heeled suede ankle boots. . . . She also chain-smoked . . . and hung out with drunken, neo-fascist public-school boys in black winkle-picker shoes.”

When Alice finally locates Jem, it is almost too late. The final steps of her search involve Jem’s unpublished writings and the birth of a child. She is briefly disillusioned by the tragic facts of Jem’s nonfantasized life, but her deeper quest, for spirituality and love, is satisfied. As in Mozart’s tale, it requires the intervention of a high priest of sorts. This figure, one Giovanni Angeletti, arrives on the scene like Pavorotti-as-Sarastro--so preposterously, groaningly larger than life that he is jarring. Operatic. Magic.

Through him and the legacy of Jem, Alice moves from pliant acceptor to initiator; she loses her lifelong stutter.

This is a truly well-written book, far more sophisticated than Rapido’s first two novels (“Brother of the More Famous Jack,” 1892, and “Noah’s Ark,” 1984). It bears reference to the fine previous works --cars seem to have “wing mirrors,” people eat “black olives in a paper cone,” and green plastic Marks & Spencer shopping bags turn up with some frequency. They are images that Trapido likes a little too much, but they are bright. The detail and dialogue in this latest treatment is generally sharper, the story more full of meaning.

As tricky as a master composer, Trapido has taken us on a spiritual journey right through the dark forest of lost friendships and broken hearts, out into the sunshine of renewal. It is, Jem would say, “very deeply to do with the nature of your being.”