The Bletchley Circle S01 E01 - Cracking a Killer's Code: Part 1
During World War II, Susan, Millie, Jean and Lucy work as code-breakers at Bletchley Park. In 1952, Susan hears of a serial killer, and contacts Deputy Chief Wainwright with her theory that there will be another victim. However the police find nothing.
The Bletchley Circle S01 E02 - Cracking a Killer's Code: Part 2
The women have three suspects, and discover that their original theory is wrong. Susan visits ex-spy master Cavendish, who gives her the name of an alleged suspect. She visits a psychiatrist, unaware that she is facing the man himself.
The Bletchley Circle S01 E03 - Cracking a Killer's Code: Part 3
Susan speaks to a man who claims he is the suspect's psychiatrist. She realizes that she has met the murderer. When the police are called he vanishes. Susan makes a final journey to unmask the culprit.