A Lapse of Faith : ANNUNCIATION, <i> By David Plante (Ticknor & Fields: $21.95; 346 pp.)</i>

David Plante is far too serious-minded to be called a mystery writer. Yet his latest novel fits the bill as a mystery, an intellectual detective story set in a literate world of trendy London art galleries, medieval Italian cathedrals and snowy Moscow boulevards.

With “Annunciation,” Plante, a prolific U.S.-born novelist who now lives in England, returns to a familiar theme: the loss of faith in a cruel world where faith is, paradoxically, both necessary and irrelevant. What is one left with, Plante’s lapsed Catholic characters wonder, after one has left the church?

His vehicle here is a meticulously crafted allegory of redemption, told in sentences so prim and clean they almost squeak. While the book’s measured, formal tone can keep the reader too far removed from the raw emotions at its core, this is a still a work of delicate plotting and beautiful complexity.

The tale is divided into two threads that gradually join. In the first, we meet Claire O’Connel, a middle-aged American art historian trying to build a new life in London after the drowning suicide of her husband, Frank.

Claire’s new suitor, a well-meaning but superficial British investment banker named George, would like to marry. But those plans are shelved when Claire’s 16-year-old daughter Rachel becomes pregnant after being raped on her way home from school.

The other narrative thread involves Claude Ricard, a young, New York-based editor of art books. Frustrated by his inability to connect with others, Claude nearly suffers a nervous breakdown after a distant relative commits suicide. After a great deal of agonizing, he accepts a temporary assignment in London.

What unites the two strands is Claire’s quixotic search for a lost painting by an Italian Renaissance painter named Pietro Testa. The art world considers Testa a minor figure, but Claire finds personal meaning in the darkness framing his compositions--and in the painter’s sad personal life.

“That (Claire) was writing about Pietro Testa, the large, dark man who had committed suicide, because Frank, also large and dark, had committed suicide, was too obvious a connection for her to think it was anything but accidental,” the narrator notes in typically deadpan fashion.

The lost painting is Testa’s depiction of the Annunciation, the New Testament incident when the angel Gabriel first revealed to Mary that she was pregnant with Jesus.

The parallel to Rachel’s situation is obvious, though left artfully unstated, and Claire’s search for the painting becomes a highly emotional personal odyssey that leads her and Rachel first to the medieval Italian town of Lucca and ultimately to a series of sparsely furnished flats and moldy attics in Moscow.

Needless to say, Plante is interested in whether religion and high art can help people find meaning in their everyday lives. But he doesn’t stop there. In some of the novel’s most arresting passages, he explores the sinister, despairing face of post-Cold War Moscow.

The narrator depicts a Russian capital full of embittered old Communist loyalists and even older sons and daughters of exiled czarist aristocrats, who have returned to a city they no longer recognize.

The book suggests the Russians have committed their own figurative suicide, first with a revolution, then a totalitarian regime, and now with political and social chaos (one Muscovite reports that he carries his windshield wipers with him because thieves might steal them off the car).

Plante also excels with minute descriptions that give the novel a remarkable sensuousness. There are vivid portraits even of minor characters, such as the underworld Russian whose “large dark eyes didn’t smile but filled with liquid, which almost overflowed the rims of his lower lids in tears.”

Unfortunately, this skill does not always translate into deep, fully rounded characterizations. For instance, the narrator tells us that Rachel, who is perhaps the pivotal character, is intelligent and strong-willed, but she nevertheless remains out of focus. Because we learn so much about Rachel only through Claire’s eyes, we remain distant from her.

Plante’s dialogue occasionally succumbs to his pervasive high-mindedness. Hotel-room conversations can quickly deteriorate into phony-sounding philosophical discourses (“(D)o you think that deep down, our impulse is not to save but to destroy?”). Such clinkers, combined with a monochromatic tone and a rather oppressive lack of humor, make for long stretches midway through the book.

Even so, one finishes “Annunciation” a little amazed at how deftly Plante has managed to weave the novel’s complicated parts into a coherent whole. It is elegant and ultimately life-affirming--a mystery in the best sense of the word.