This rich, sprawling, ambitious, likably ungainly story--a sequel to Smith's Victorian-period mystery, The Vanished Child (1992), and the middle volume in a projected trilogy--may frustrate connoisseurs of the well-made novel but will amply reward readers seeking a ripping yarn with provocative and substantial things to say. Talented pianist Perdita Halley and Baron Alexander von Reisden now find themselves in Paris in 1910, the year when the Seine overflows, flooding the city and climaxing a bafflingly intricate plot that includes the unsolved murder of a street prostitute nicknamed ``Mona Lisa,'' a scheme to steal from the Louvre the famous painting that is her namesake, and the investigation of charges that the highly marketable works of the late Impressionist painter Claude Mallais may in fact be forgeries, and that Mallais's widow may be something other than the docile helpmate she appears. Smith adroitly grafts onto these intertwining plots the conflict that engrosses the embattled Perdita: whether to pursue the musical career she was surely born for, or to submit instead to her needful lover's embarrassed ultimatum (``I want to be more important than the piano''). The author convincingly evokes the period through hundreds of exquisitely selected details, and makes the vivid secondary characters--including unmistakable simulacra of Colette, Gertrude Stein, and Picasso--altogether credible both as distinctive individuals and as participants in the complex melodrama that surrounds, and unexpectedly transforms, her resourceful heroine. Though it's crammed to bursting with resonant particulars and stylish, often epigrammatic writing, the novel moves rather too slowly--and the convolutions of its narrative are a little too easily foreseen (for example, few will fail to guess the outcome of the Claude Mallais subplot). For all that, the thick ambience, the forthright feminist subtext, and especially Smith's gritty and appealing heroine make for intellectual stimulation of the highest order--and should make most readers impatiently eager for the completion of the trilogy.