Bletchley Circle

In 1952 London, former code breaker Susan spots a pattern in a string of murders of missing girls. When she brings her discovery to the police, they act on her information but find no evidence. Despondent and defeated, Susan contacts her old friends who worked with her at Bletchley Park during WWII. Working together, maybe they can save another girl before she becomes the next victim.

The women have narrowed down their suspects to a list of three men, which Susan takes to Scotland Yard but finds little interest in their theories. With the clock running out before another girl is taken, they decide to do a vector analysis on the data and uncover a significant detail. But when they try to bait the killer, their trap goes horribly wrong.

Susan and her code-breaking 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.