The Bletchley Circle

Susan Gray spots a hidden pattern in a series of murders and enlists fellow code-breakers to try and track down the killer.

Susan and the group use Lucy to lure in a suspect.

Thrown into a chilling confrontation with the murderer they have tracked down, Susan and the other women become locked into a more dangerous game of cat and mouse.

Former Bletchley Park worker Alice Merren is in prison awaiting trial for the murder of the eminent scientist John Richards; Jean attempts to regroup the circle in order to help establish the innocence of one of their own.

Following the discovery of Lizzie Lancaster's true identity, the women race against time to establish Alice's innocence and save her from hanging.

After Millie is released from her abductors, she -- along with Alice, Jean and Lucy -- makes a horrifying discovery.