Former Bletchley Park worker Alice Merren is in prison awaiting trial for the murder of the eminent scientist John Richards. Driven by her belief in Alice's innocence and that she is hiding the truth about John's death, Jean attempts to regroup the circle in order to help establish the innocence of one of their own.
Elenco: Rachael Stirling , Julie Graham , Sophie Rundle , Anna Maxwell Martin , Nick Blood .