In sales and popularity, Quick's (vaguely) Regency-period romance formula continues to wear exceedingly well after its 11 other manifestations, all with eye-wink titles (Mystique, 1995, etc.). Here, again, are a hoydenish heroine, mighty of will, and a titled foe-turned-lover, mighty of, well, just about everything. They'll collide, sizzle, and finally meld in True Love while solving mysteries and thwarting enemies. Stouthearted Imogen is not the least put off when encountering, in her late uncle's sarcophagus/bed (uncle collected odd artifacts), a caped figure--none other than that of Matthias, the Earl of Colchester, complete with icy eyes and a white streak in his ``midnight-dark'' hair. Imogen plans to draw Colchester into a scheme to avenge what she believes is the murder of her friend Lucy at the hands of Lucy's detested husband Lord Vanneck. As a scholar and expert on the customs and artifacts of the ``lost island of Zamar,'' Matthias is necessary to further Imogen's plot. (Never mind why.) Soon the pair--``Coldhearted Colchester'' and ``Immodest Imogen'' (the latter societal rep imposed when in the past Imogen was surprised, innocently, in a bedroom with Vanneck)- -are weaving and feinting through the intricacies of the ton. By the close, there are three murders left to solve; a lost journal; a duel attended by a corpse; Matthias' young sister used as a pawn in a dastardly plot; and a dusty showdown in a Zamar museum. While crises loom, Imogen--full of purpose and cries of ``bloody hell!''- -discovers the thrills of ``Zamarian'' lovemaking. A tidy package: Lively lovers, a tiny but respectable mystery, sex both lavender and jovial, and good humor throughout. More of the saleable same.