The first episode reveals that Station X was the cover name for the World War II radio interception station co-located with the Government Code & Cypher School at Bletchley Park. In 1938 the British Secret Service bought Bletchley Park, installing wireless receiver (call-sign: "Station X") to pick up German messages. A small group of aristocratic codebreakers visited the Country house with their staff and butlers under the guise of "Captain Ridley's shooting party" to establish its suitability. With war Military Intelligence began to recruit various skillsets. Geoffrey Tandy, a marine biologist expert in Cryptogams, was selected when someone confused these with cryptograms. The youthfulness of many staff was noted by biographer Andrew Hodges, who noted that young people had the keys to the Reich.
The programme includes analysis of discusses The Herivel Tip, an imaginative cracking method which relied on the laziness of the Enigma operators when setting up their machines in the morning. Also explored is the role of Station X in the air and sea battles of 1941 and the part played by Alan Turing in cracking Germany’s naval messages.
The programme starts with the 1941 Invasion of Russia. Contributors include David Kahn In a speech Winston Churchill publicises mass executions and the systematic slaughter of Jews, feeling the outrage greater than the imperative to protect the source. Loris Gherardi's role in the Theft of the Black Code, and its continued use under Colonel Norman Fiske and Bonner Fellers, is reconstructed. Also, Turing’s development of the Bombe, a machine used to automate the code-breaking process.
This episode covers the Enigma and Lorenz cipher machines, and the role of Station X in the Battle of the Atlantic and D-Day landings. Also, the lighter side of life at Bletchley Park is also addressed, as well as the future of those who left at the end of the war.