The Bletchley Circle is a television mystery drama miniseries, set in 1952–53, about four women who used to work as codebreakers at Bletchley Park. Dissatisfied with official failure to investigate complex crimes, the women join to investigate for themselves.The first series of the miniseries, produced for ITV, was originally shown in the UK in 2012, and had its U.S. audience premiere in April 2013, on PBS. A second series was broadcast on ITV in January 2014, and on PBS in April 2014.