Madison Dix is an agent with British Naval Intelligence.
That might make it sound like she is 'in' the Royal Navy but that is so very much incorrect. Not only would Dix never once consider joining the military at any time for any reason, considering her larcenous attitudes towards anything and everything, they would never accept her. 'They', though, is everyone associated with that organization except Admiral Cutter, known to his subordinates as the 'Owl' due to his penchant for working late into the night.
Instead of an aged, retired or nearly so, crusty individual, Cutter was someone that Dix immediately took a liking to, calling him "handsome, tall straight backed with green eyes and a sexy seaman's beard". Which is why on their initial encounter when he caught her pilfering a valuable necklace from a rich woman's safe, she immediately offered to 'pay' for her crime with a nice roll in the hay with the older man (although in this case it would be a romp on the pool table). He refused with a shocked huff and the look he gave her made Dix feel like "being caught smoking by your father".
Cutter refers to Dix as a "miracle", pleased with her expertise with four languages, not to mention being an accomplished magician and being "an acrobat extraordinaire", the former coming from the teachings of her stage magician father and the latter from her trained mother. Which is why it was no surprise, except to Dix, when he offered her a job working for him. Dix, as is her nature, immediately worried it would mean giving up her secret life as a cat burglar by having to go straight. Cutter promptly allays those fears with, "I need an honest-to-goodness talented thief, not another patriotic do-gooder".
Then worried that Dix would have to give up whatever goodies she encountered in her jobs for Cutter, she is intrigued when he vows that she would have to turn over "only the items I want. The rest you can keep". Now she was really interested.
The offer of a job did not come with immunity, he made sure she understood. "If you get pinched while freelancing I'll not lift a finger to get you out of jail. Get caught while on Bureau time and I'll do exactly the same." That took a bit of the luster off the shine but she was still sold on the idea. That fact that she would be stealing "for the safety of your country and empire" might or might not have had a part in her agreeing, it is really hard to say for certain with Dix.
The adventures of Dix take place in the years just before the start of the Second World War and her activities will be largely in conflict with ace Italian spymaster, Count Facchini, a close friend of Mussolini and a man who will prove to be a terrifically dangerous nemesis to Madison Dix, and vice versa.