布莱切利四人组第二季第1集

During the war Alice Merren was one of Bletchley's brightest code-breakers. Now it is 1953. Lucy has a clerical job for Scotland Yard, Millie works as a German translator and Susan a housewife perturbed that her husband's promotion may take them overseas. Jean visits Alice in prison, awaiting trial for killing her old flame and Bletchley colleague John Richards. Jean is convinced of Alice's innocence and persuades her friends to investigate. They discover that John sent flowers to a young girl, Lizzie Lancaster and a search of her flat reveals she is in possession of a classified military file and a press cutting of an incident where military personnel were injured by a chemical experiment on Salisbury Plain. The women save Lizzie from a hit and run and Jean correctly assumes that she is Alice's daughter. The Bletchley circle believe both mother and daughter have been set up by John's killer who was also responsible for the Salisbury Plain incident.