The Rose Code deals with two time periods, the first starting in 1940 and the second taking place in November 1947. In 1940 three women come together and become the closest of friends because of their work and because they board in the same house/room. These three women are recruited to work as female codebreakers at Bletchley Park and the women are tied together by the secrecy of their work, knowing the Official Secrets Act of 1939 prevents them from speaking to anyone of what they do. A 1942 security warning emphasized the importance of discretion even within Bletchley itself: "Do not talk at meals. Do not talk in the transport. Do not talk travelling. Do not talk in the billet. Do not talk by your own fireside. Be careful even in your hut." The very need for such secrecy throws these three women into friendship as nothing else could do.