The city mysteries were a nineteenth-century bestselling transnational literary phenomenon that combined radical politics and sensational fiction, adapting historical events along with devices from already existing popular narratives. Born as answers to the new megalopolis, these mysteries were supposed to work as calls to political action by exposing the vices, crimes, and corruption of the city's wealthy elites, in contrast to the miserable conditions of honest, victimized workers and middle-class families. However, the ideological coherence of city mysteries was often compromised by their voyeuristic emphasis on the most sensational and lurid aspects of the same social evils they aimed to eradicate in the first place. This article is built upon the hypothesis that, in a very different context, Joker (2019) has filtered staples of the city-mystery genre through the aesthetics of contemporary popular culture, in order to produce a politically mystifying but unequivocally provocative film.