Now in Knopf Paperback, the third book in the exciting mystery series starring seventh-grade ace detective Sammy Keyes. Sammy is working off some junior high detention time at St. Mary's when Father Mayhew discovers his ivory cross has been stolen Sammy becomes the prime suspect and must use all her sleuthing talents to find the real thief. But when three singing missionaries, two jealous nuns, and one bumbling Brother get mixed up in the mystery, it's not so easy to tell the saints from the sinners.