Beth Johnson is an agent with British Intelligence.
Considering the year her activities commence, 1664, there really is no organized agency in place, just the small group of operative working under the direction of HM government's current spymaster, Sir Alan Strange. That mysterious, and apparently powerful man, takes the protection of the country, and its sitting monarch, Charles II, very seriously. "Tall, dark and mysterious, spymaster Alan Strange seeks out candidates from all walks of life, spotting the potential for high-quality agents in the most unlikely of places. Ruthless but fair, Strange is an inspiration for his recruits, and trains them well."
Johnson is a young woman of considerable beauty and growing more so as she ages. She is 15 years of age which sounds quite young to be employed as an operative but considering the period of time in which she lives and life expectancy then being not much more than 40, starting so young does not seem quite so peculiar.
Johnson is also a rising figure on the British stage, working at the King's Theatre. The prohibition against females acting professionally in the theater was only repealed a couple years before we meet Johnson, shortly after the Restoration of the Crown. Many of the older actors greatly resented the female presence as they had earned a good living playing the female parts but the audience were more than eager to accept real women in female roles and Johnson was already well received in a couple of productions. She is said to be "tall and beautiful with chestnut brown hair and green eyes" who had "risen from lowly depths as a foundling abandoned on the steps of Bow Church to become a celebrated thespian", not to mention a pretty good espionage agent.
Johnson got her secondary occupation as operative when Strange went backstage after a performance to ask if she would also be interested in serving the government. She "knew that the reason she'd been asked to become a spy was because she worked in the King's own theatre. Her experience as an actress meant that she was an expert in disguise and role-playing, and she was proud to serve her King, both as an actress and a secret agent. But she was growing a little tired of being given jobs that revolved solely around the theatre. Hopefully, if she got this job right, she would be asked to do something a little more adventurous next time..."
Johnson will learn quickly to be more careful what she asks for with the greater adventures invariably came great dangers.
Helping her out on these new missions are two young men also made into field operatives for Strange: John Turner and Ralph Chandler. The latter is a "former street urchin [who] has led a rough-and-tumble existence, but his nefarious beginnings have their uses when employed in his role as one of Sir Alan Strange's spies, working in the service of the King." The former is a "junior clerk at the Navy Board" who "imagines himself in more daring, adventurous circumstances - and he soon has the opportunity when he meets Beth Johnson and becomes part of her gang of spies".