Set in a spot-on sleepy Tennessee town circa 1952, Phantom Nights is near-bursting with the potential for top-rate pulpy thrills (''He had the face of a cranky fetus,'' Farris writes of one character). And yet too often Farris settles for something more middle-of-the-road. Alex Gambier, a brazen kid of about 14, mute since diphtheria stole his voice box, tests his mettle by lying underneath oncoming passenger trains. That's how he meets Mally Shaw, a black nurse whose instant friendship with Alex is cut short when she's brutally raped and murdered. Farris brings Mally back as a ghost, but his graft of Southern gothic doesn't take when he too often sidelines Alex in favor of his nice-but-boring sheriff brother. We're promised spicy gumbo, but instead we get good-enough grits.