Victorian England? Not quite. A great queen really sits on the throne, and the sun never sets on the British Empire - but the cozy mansions of London are adjacent to skyscrapers, balloons hover over the streets, people are served by mechanical servants, carriages move on steam, and science and magic have equal rights. Here, a person’s fate is determined from birth. The impoverished orphan Molly Templar understands perfectly well that she will have to join the ranks of the “night butterflies” of the capital... The nephew and pupil of a wealthy businessman, Oliver Brooks, has been preparing since childhood to enter into a prosperous business for his uncle... But suddenly Molly and Oliver's lives change dramatically. They meet in an hour of terrible danger - and are forced to support each other in the face of certain death. In their wake are ruthless hired killers, systematically destroying all their loved ones and acquaintances. What are the guilt of the young man and girl, who have not harmed anyone? Who ordered them? And most importantly - for what? Molly and Oliver understand: the answer must be sought in their origins, which so far remains a mystery to both of them, and in the magical abilities that are gradually awakening in them...