This article traces clandestine film censorship in colonial Hong Kong during the Cold War. Based on film studio records, press coverage, historical accounts, and recently declassified government documents, albeit limited and incomplete, the article examines sample cases and controversial foreign and Chinese films to throw light on the predicament of cross-border film exhibition in a distinctively politicized period. The evidence and arguments in this study point to a different conceptualization of transnationality and boundary-crossing of cinema grounded in its specific historical and geopolitical configuration. It is less about the easy traffic of capital, human resources, commodities, and ideas across the border than the dangerous trafficking of movie images, ideologies, human actions and propagandas that could destabilize the territorial boundary and its political status quo. Film screening and viewing in the colony are subject to strict official surveillance to quarantine the visuality of politics in the shadow of Cold War paranoia.