In her latest off-the-rack tale of domestic miseries, Chamberlain, (Reflection, 1996, etc.) leads off with a sure-fire grabber--a young mother who flees cross-country with her adored baby son, after losing a custody battle. Along the way, she confronts a romantic complications, a mystery, and fatal violence. Susanna Miller, having seen the custody of 11-month-old Tyler (survivor of a serious heart condition) awarded to ex-husband Jim and his new wife Peggy, knows what she has to do. Beginning with a night exodus from Boulder, Colorado, Susanna will travel east, eventually settling in Maryland. She'll adopt the name ``Kim,'' and little Tyler will answer to ``Cody.'' Kim's only link to Boulder is the syndicated radio show of the man she loves--disc jockey Linc Sebastain, who once served a short sentence for murder. His victim was Susanna's childhood tormenter, whom Linc had known as a neighbor years before. It's Linc's past, and his present involvement in her life (along with her own few days in a mental institution), that contributed to Susanna's court KO. In Maryland, jumpy Kim finds pleasant people, particularly a local artist, the attractive Adam, who pronounces her talented. Adam makes advances, Kim communicates with Linc via fax, and Linc responds on the airwaves. Kim must soon make a terrible decision, however, involving her knowledge of the route of a serial bomber: If she alerts the police, she will certainly lose Cody permanently. Meantime, back in Boulder, Peggy, essentially a good sort, is rapidly learning that Jim is a liar and a cad. She readies a surprise, while Kim sets off to waylay the crazy, deadly bomber advancing in the dark. There'll be a nick-of-time appearance, as well as a sacrificial demise. Chamberlain paces the flight-or-fight phases of the runaway mother's story with thoroughly professional ease: Her stories never cut deep, but they do skim along at a cheerful speed. A reliable time-passer.