When Cathy and Martin Adams decide to have a baby by donor insemination, Cathy's mother, Joan, blames her son-in-law for the "unnatural" act. Bitter recriminations follow and Joan's subsequent murder would appear to be a clear-cut case. But all is not as it seems: Taggart discovers that Dr. Miller of the fertility clinic has been donating his own sperm and that about 60 couples who attended the clinic are now bringing up a "Miller" child. More creepy discoveries lead the Taggart team on a terrifying hunt for the killer before he strikes again. This book is based on the successful Scottish tv detective drama.