Follow four ordinary women with the extraordinary ability to break codes – a skill honed during World War II when they worked undercover at Bletchley Park, site of the United Kingdom’s main decryption establishment. Now, in 1952, Susan, Millie, Lucy and Jean have returned to civilian life, keeping their intelligence work secret from all, including family and friends. A series of ghastly murders targeting women, however, re-unites the team as they set out to decode the pattern behind the crimes.

Part 2 of 3
When Scotland Yard dismisses the women’s theories, the group realizes it’s up to them to stop the killer before he takes his next victim. They identify a suspect and use Lucy to lure him into a trap, but their plan goes badly awry and Lucy is assaulted. Shaken, the women take a different approach, contacting former war department members. Susan plans to meet with a psychiatrist whom she believes has helpful information, completely unaware of the danger that awaits her.