In the shadowed and sepulchral Florence of the 1690s, with the Medici dynasty in steep decline and the city cowed by the puritanical regime of Cosimo III, a sculptor in wax receives a commission from the Grand Duke himself.
Zummo, our hunted, watchful Sicilian narrator, has fled his home island under a cloud after savage quarrels with his brother. Now he must make a statue of a perfect, naked woman. For the wax-artist, a late-Baroque Damien Hirst who specialises in macabre cabinets that depict (for instance) the putrefactions of the plague, it's a humdrum if well-paid job: a work of "pure surface".
But a conversation with Jack Towne, a sinister English art dealer, sets Zummo on the right track. He has to inject into this routine task a trademark dose of "liminality": his border-blurring quality of "ambiguity", and so forge a piece "that functioned on at least two levels".
In due course, he does so, in ingenious - and unsettling - ways. Equally, followers of Rupert Thomson's fiction may feel that Secrecy represents something of a wax Venus for its author. Over eight varied but distinctive novels, and one blazing memoir of family grief and strife (This Party's Got to Stop), Thomson has merged the pulse and pace of a thumping narrative heartbeat with an eerie and visionary gift for mystery, puzzle and surprise.
Like a Borges script for a Hitchcock film, enigmatic but suspenseful, the Thomson novel moves via electric jolts of menace, malice or morbidity that lend a flesh-tingling charge to every twist. From the mind-bending dystopia of Divided Kingdom to the delirious Amsterdam ordeals of The Book of Revelation and the disorienting fable of blindness and insight in The Insult, Thomson's immaculately chilled tableaux of crime and dream create a unique microclimate of existential noir.
For his devotees, Secrecy read at a gallop - and it pulls like a runaway thoroughbred - feels at first a bit like Thomson Lite. It has the contours of an expert genre piece. This period Tuscan romance comes fully-furnished with the outsider artist, the noblewoman with a tragic back-story (Cosimo's estranged French wife, Marguerite-Louise), the poor, persecuted but resourceful heroine (Zummo's inscrutable inamorata, Faustina), some droll but wily Florentine street-urchins and lethally sophisticated courtiers - above all, the monk-thug Stufa.
Thomson carves them all with ferocious glee. Zummo becomes the man who knows too much in a secret-stricken city of "blind alleys and dead ends". A swerving plot rides hard towards a fabulously atmospheric showdown in snow-scoured hills.
Yet, as always with Thomson, that "liminality" breaks in to deepen and sharpen the mood. The writing bristles with laconic but (in the poetic sense) metaphysical similes, from impending death like a settling of "dust in sunlight, sediment in wine" to elusive truth as "a key on the floor of the ocean, its teeth mossy, blurred".
As a stylist, Thomson comes far closer to the florid, livid world of the late Baroque than any costume-drama potboiler. In his Florence, the "object of beauty" becomes the "object of violence". Scene after scene trembles with breath-stopping tension on the edge of bliss or dread. No one else writes quite like this in Britain today. Newcomers to his work who open this box of secrets will hurry to snatch others from the shelf.