The second appearance of Sigismondo, the Renaissance trouble- shooter for Duke Ludovico of Rocca, finds him at the bedside of expiring Princess Oralia while her husband, evil Prince Livio, beheads his young son--believing that he and his twin sister, Lady Minerva, were begat by another. Sigismondo and his half-witted companion Benno flee with Minerva, disguise her as a peasant boy, and head for Fontecasta, a supposedly haunted castle but actually the home of a nobleman blinded by Duke Grifone. Meanwhile, during preparations for the feast of Saint Bernardina, the Duke's advisor, Cardinal Petrucci, is set ablaze and killed, and his sister, the bossy Princess Corio, hires Sigismondo to discover whodunit. Deftly maneuvering through political intrigues, Sigismondo discovers clerical improprieties (love affairs, bribes), treacherous mercenaries, household spies, avid torturers, eager Jew-baiters, and crafty magicians, and manages to outwit them all. Teeming with fleas, rancid food, bloodthirsty peasants, conniving nobles, lecherous prelates, thumbscrews, saintly relics, and political feuds. Lively but, like Eyre's Death of the Duchess (1992), can't shake the YA label with its jampacked this-is- history-kids tone.