Masterpiece Mystery It's 1946, and in the brewing Cold War climate of post-war Britain, Detective Chief Superintendent Christopher Foyle and his loyal friend Sam find themselves adjusting to a new era of secrets, intelligence, and security as the Ir... (more)on Curtain descends and MI5 comes knocking. In "The Eternity Ring", When Foyle returns from America, MI5, suspicious that British atomic research has been infiltrated, asks Foyle to investigate whether a Russian spy network could be at work in the heart of London. In signing on, he's reunited with Sam, who is now married and working for a scientist involved in the development of the atom bomb.