Exile. Princess. Thief. After years of running from the Emperor of Russia's assassins, Ekaterina "Kat" Dashkova has finally found an unlikely home in Philadelphia under the tutelage of Benjamin Franklin. When a mid-level government official is found wandering colonial Philadelphia without his clothes—and his last two years of memories—Ben and Kat suspect otherworldly forces at work. Neither of them know that a dark revolution lurks beneath the veneer of civilization, ready to unleash its malevolent magic unless Kat makes a grim sacrifice.