Hanno Stiffeniis, a young magistrate, has been called to KÞonigsberg to assist in the investigation of an enigmatic string of murders. Is it part of a plot formed by Napoleon's spies to undermine the Prussian king or the work of a solitary, unknown killer? The case would seem unsolvable, were it not for the assistance and unmatched intellect of his mentor, Immanuel Kant. Together Stiffeniis and the elderly, eccentric philosopher must track down the killer who has the city of KÞonigsberg by the throat.