Bletchley Circle

Susan tells the other women that she came face to face with the killer - and he let her go. It soon becomes apparent that he's becoming obsessed with her. Following the death of a former spy who had been helpful in identifying the perpetrator, the women consider whether to continue their pursuit, but they know if they don't find the killer, he'll move somewhere else and more girls will die. Their investigation resumes. Cleverly planting false clues, the murderer leads Susan into a trap.