By Vanessa V. Friedman
May 26, 1995 at 04:00 AM EDT

In 17th-century Spain, young Queen Maria Luisa lies on a bed in her castle and dies painfully; many floors below her in the dungeon, a peasant girl is tortured for being a witch. Weaving back and forth in time and caste, Poison is the story of the how, what, and why of their lives: how the Queen came over from France to marry the sickly King Carlos, why she incurred the royal wrath, what is causing her demise; how the peasant girl came to love a priest, why she is being tortured, what has been happening in the countryside. In historical fiction there is a fine line between re-creating a time in a way that is absorbing to a contemporary reader and parodying it in a sort of romantic, bodice-ripping manner. For the most part, Harrison manages to be entirely convincing in her maiden effort. B+