Surely Harriet owes her name to the titular spy of Louise Fitzhugh's classic children's novel. She's in the literary tradition of fierce, impossible, tomboyish girl children: bossy to her peers, frank to adults and possessed of an uncompromising dignity that frequently brings her grief. "It's awful being a child," her most astute great-aunt commiserates, "at the mercy of other people," and that's especially true for this child. Twelve years after her brother's death, Harriet's sister Allison is sweet, pretty and dreamy in the wilting mode of Southern femininity, but Harriet is no Scarlett O'Hara: "She argued with Edie and checked out library books on Genghis Khan and gave her mother headaches." She is the sort of child who, when asked by a Bible class teacher to write down her summer goals, hands in a piece of paper with a single black dot on it -- that's how the pirates in "Treasure Island" informed a man they intended to kill him. In short, she is an irresistible character, and the engine that drives the book.