When the Russell family moves in next door to 15-year-old Leah, she immediately fastens herself to them, or tries, and seems especially drawn to the unmotherly dentist mother despite the absence of encouragement. Leah's own mother is dead; Leah herself has been turned off sex at age six by the discreetly mentioned bedroom visits of her first step-father; and she now lives with her mothefts sympathetic third husband, Moe, who is currently upsetting their comfortable relationship by taking up with a woman friend. Then Matt Russell, 17, decides to raise a baby he has fathered in a very passing encounter--the reasons for his decision aren't clear even to him, but he can't let the girl abort his offspring--and Leah forms an instant, obsessive attachment to the baby, confusing its identity with her own, and eventually kidnapping it to ""save"" it from Matt. The story, told in rigidly alternating chapters from Leah's and Matt's viewpoints, ends patly with Leah recovering under psychiatric care and Matt taking off for a new life with his child. The novel never transcends its situation-centered premises, but it has more veracity and independent life than many such conjectures. Leah's disturbed behavior is credible enough, Matt's conflicting feelings toward the baby are well portrayed, and his family (especially the mother) is refreshingly original. ""This isn't time for man-to-man advice,"" Matt's father tells him toward the end. ""But when the time comes, remember this. Pick a woman who's challenging."" This is no challenge, but at least it moves along the predetermined path under its own steam.