Once again, as in The Last House-Party and Hindsight, Dickinson offers a dark, dry, gently bifocal mystery: the tale of a bygone tragedy, followed by present day insights into what really happened. The brisk narrator throughout is Lady Margaret (""Mabs"") Millett, but she's only 21 when she writes the novel's first half--all about the events of the preceding year. Circa 1953 Mabs is the reluctant heiress to the family estate of Cheadle--programmed by her widowed mother for a wealthy marriage (Cheadle's upkeep is costly), jealous of her twin sister Jane's relative freedom, bored with the London debutante scene. So Mabs is oddly responsive when she meets cool, sardonic, mysterious Amos Brierley at a party: he's 50, an ""ugly little man,"" yet compelling--especially after he instantly provides Mabs with a dream-job at Night and Day magazine (which he owns), writing parodies of the deb world. Soon, in fact, virginal Mabs finds herself calmly agreeing to become Brierley's secret mistress, even though he never mentions love (let alone marriage). He sets her up in an apartment near his; she asks no questions about his enigmatic dealings; they travel to Barbados, where Mabs meets Brierley's ancient octoroon mother (a bygone plantation heiress); no one knows their secret except twin-sister Jane (and the magazine's disapproving doyenne of society gossip). But then Mabs' witchy mother Finds Out--reacting with snooty horror and greedy blackmail. And, shortly thereafter, as Brierley's dicey financial setup starts to topple, he flees the country--only to be gunned down in Rio a few days later. Who killed Brierley and why? Where did his shady funding really come from? Above all, did he love Mabs--or just use her? Mabs won't learn the answers until 30 years later--when, in her very different middle-aged world (bestselling novelist, disappointed mother of two, guardian of the Cheadle estate), she puts together a scattering of clues from past and present. True, these final revelations--rather clumsily announced--don't quite seem worthy of all the buildup; and the deceptions involved don't have the chilly resonance of the House-Party and Hindsight secrets. But this is a curious, intriguing diversion most of the way through--always atmospheric, often amusing, and sometimes surprisingly moving.