Bad news for the Senior (Citizens') Prom at the Oak Terrace Retirement Home: The prom king, retired department-store-owner Brady O'Hara, has been strangled, and his onetime girlfriend, Benni Harper's meddlesome old fourth-grade teacher Rose Ann Violet, has been smothered with a convenient pillow. Folk-art- museum curator and quilt specialist Benni (Fool's Puzzle, 1994), who's been helping to organize the prom, switches hats without missing a beat to investigate the double murder, despite the dark warnings of her macho lover, acting San Celina, Calif., police chief Gabe Ortiz, and soon stumbles on Brady's guilty secret. In the months after Pearl Harbor, he went around the county buying up stores, farms, and ranches from Japanese-Americans facing internment--so that after the war he could sell them back to their owners without making a penny of profit. Why would skinflint Brady, whose own brother was killed in the opening weeks of the war, be so solicitous of his Japanese neighbors? And why would vengeance for his irrational act of kindness finally catch up with him 50 years later? Sturdy mystery-mongering bolstered (if that's your pleasure) by some heartfelt romantic rivalry between Gabe and Brady's swaggering great-nephew, Clay, who takes time out from his own pursuit of Benni to admit that, yes, he had a powerful motive for killing his uncle. You got a problem with that?