Cardia Beckford can recollect her father Isaac and the home where she lives alone, dreaded as a monster by the townspeople—for she bears a terrible chemical in her body. The constantly beating heart, also known as Horologium, was implanted in her chest by her father and has the potential to generate endless power. It does, however, cause her skin to ruin whatever it comes into contact with. Many people in London are looking for the Horologium, including the terrorist group Twilight, with whom Isaac is said to have intimate relations. To get the power of the Horologium, the British military compels Cardia to leave her house as a prisoner. On the trip, however, she is kidnapped by the gentleman thief Arsène Lupin, who promises to take her heart.