The true story of Britain's most infamous spies as it follows them from their iniitial recruitment by the KGB in the mid 1930's, as students at Cambridge University, through the end of their careers in the 1950's. The series attempts to look beyond their crimes by focusing on their dedication to their cause and to each other and how they belived they were serving their country. Four-part drama telling the story of Guy Burgess, Donald Maclean, Anthony Blunt and Kim Philby.