Jacobs introduces Minneapolis-based Devon MacDonald, ex- teacher who's lost husband and young son and now partners gruff, warm-hearted, obese Sam Sherman in his detective agency. Devon is approached by Dr. Ben Levy, donor to a sperm bank years before. His only child, a victim of leukemia, can possibly be saved by a bone marrow transplant from a close relative. Can Devon and Sam locate any children born of Levy's seed and persuade them to be tested for marrow compatibility? A big order, especially since the sperm bank has long been defunct, but the real crunch comes when Devon encounters the Levy's only hope, the Hoffman family. Fascist, wife- beating Gil Hoffman was kept in the dark about wife Myra's use of another man's sperm to father son Tyler. In record time Hoffman is dead and Ben Levy is arrested for his murder but Devon has an ace up her sleeve that produces the real killer and the hope of a happy ending. Original plotting, competent writing and a heroine who's gutsy but no Superwoman make this one a welcome addition to the genre.