Dr Peter Stott is a scientist working at a Cancer Research Institute in London and is happily married to artist Anne, who has a secret. At the institute, Peter suspects corruption in a drug-testing programme and both he and his assistant, Susan, become amateur detectives and uncover a 40-year trail of deceit, which explodes into violence. Peter becomes a scientific celebrity, but illness in the family and a later betrayal destroys his world and he takes revenge. Anne's secret and her ultimate retribution are revealed in a chilling surprise ending.