The Bletchley Circle

Susan, Millie, Jean and Lucy have returned to their normal lives, but when Susan identifies a hidden pattern in a series of murders, she enlists the help of her former colleagues to crack the case.

The women close in on the killer of the five girls, narrowing their list down to three suspects. A shocking discovery forces them to change their theories and they set a trap to catch the culprit.

Susan and her allies seem to have finally tracked down the murderer...and attempt to confront him. As the women get closer to their target, they are forced to put themselves in grave danger.