Moscow, 1956. Four women who are tied by the military past: work in the special department of the GRU, 11 years later converge again to conduct investigations and help the investigating authorities in especially complicated cases. With phenomenal analytical skills, Irina, Anna, Sophia and Katerina risk themselves, as well as the well-being of their own families, in order to get on the trail of criminals who threaten the lives of ordinary people and the whole country. Cipher is a Russian television detective based on the British mini-series The Bletchley Circle. The working title of the series is "The Ciphers". The series is produced by Sony Pictures Television, Lean-M and the Pobeda Production Association. The premiere of the television series took place on March 11, 2019 on Channel One.