1917. Vienna. File clerk turned British agent, Fiona Figg, is more comfortable wearing a fake mustache than a ballgown. When a royal ball ends with a royal body in the middle of the dancefloor, Fiona trades her dancing slippers for practical oxfords and sets out to investigate. As she tracks her nemesis, the Black Panther, from Vienna to the Austrian countryside, a hunting accident makes her rethink her loyalties. Can Fiona prevent the Black Panther from striking again, save her own skin, and find a decent cup of tea, all before the enemy’s emperor realizes she’s a spy?