A cleaner finds a jacket lying on the floor of a top secret laboratory and then suddenly discovers there is a dead body inside the jacket. The police investigation is hampered by the secret research being conducted at the laboratory in the Fylde. Painstakingly the police review the suspects, but it becomes clear that the murderer probably came from overseas, prompted by the need for an organisation to find out what type of research has been achieved in the laboratory.
One clue leads to an investigation amid the Vietnamese community in Nottingham, but the suspect appeared to have fled to Madrid where there are no extradition facilities for mere suspects. The police consider how they can lure the suspect back to the UK.
A simple murder investigation becomes an international chase for the killer as the police forces in Germany and France become involved when it is discovered that the suspect was originally recruited by Stasi in East Germany before unification, but then fled to Marseilles and then on to England to escape custody following a murder conviction.
At the last moment the Special Branch from Scotland Yard becomes involved and the murderers are arrested.