"Television producer Fliss Benson receives an anonymous card at work, with sixteen numbers on it, arranged in four rows of four--numbers that mean nothing to her. One the same day, Fliss finds out she's going to be working on a documentary about three crib death mothers wrongly accused of murder: Helen Yardley, Sarah Jaggard, and Rachel Hines. All three women are now free, and the doctor who testified against them, child protection zealot Dr. Judith Duffy, is under investigation for misconduct. For reasons she has shared with nobody, this is the last project Fliss wants to be working on. Then Helen Yardley is found dead at her home, and in her pocket is a card with sixteen numbers on it, arranged in four rows of four . . ."--P. [4] of cover.