In a Neo-Victorian London of mechanical horses and aerial gondotrams, airship engineer Jasper Kendall Asher has a bright future ahead as the youngest member of the Engineers Order and a secret agent in Her Majesty's service. But a terrible accident brutally changes the course of his career, sending him instead to a dull life as a mechanic among the poor of St. Giles. Three years later, unusual circumstances give him the opportunity to return...