In this episode, we find England alone - a protestant nation in a largely Catholic Europe. Then, 12 years into Elizabeth's reign, the Pope declares her a heretic, which in the hearts of England's Catholics gives them permission to kill her. Queen Elizabeth looks to her spymaster William Cecil to stop the Catholic assassins getting through. Cecil establishes a huge espionage network - England's first secret service. His spies break Catholic conspiracies at home and abroad.