The women suspect that corruption within the vice squad is to blame for the lack of action by the police and therefore they will have to catch the gang themselves.
Alice contacts her former Bletchley colleagues when Millie is kidnapped, as she suspects it is linked to black market deals and does not want to involve the police.
In the concluding part of this story, the team continues to search for proof that Alice is innocence, but they discover evidence that points to a high-level conspiracy.
When Alice Merren, a former Bletchley Park colleague, is charged with a distinguished scientist's the murder, Jean reunites the women for their second case.
Thinking she knows the identity of the killer, Susan returns with the police, only to find him gone. Later, at home, she discovers a coded message with Cavendish's address, which in turn provides another clue. By following the thread, Susan could be walking into a trap.moreless
When Scotland Yard dismisses the women’s theories, they realize 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.moreless
It is now seven years after the end of the World War 2 and four women, all ex-codebreakers from Bletchley Park, have got used to their mundane civilian lives. Following a spate of local murders, Susan starts collating information about them to see whether she can use her analysis skills to spot a pattern. Unable to convince the police to take her seriously, she turns to her former colleagues for help.moreless