When Roddy Winger is released on appeal after serving twenty years for the murder of a nightclub hostess - a crime he always claimed he did not commit - his case gets re-investigated by UCOS - The Unsolved case squad. The squad is to be made up of some of the best retired officers available. The squad gets headed up by Det Supt Pullman, who is moved after shooting a dog in a hostage rescue gone wrong. With Jack Halford she sets out to build her team and investigate the case.