Why did Hong Kong protestors choose a symbol of former oppression – the old colonial flag – as a banner for their fight for democracy, rights and autonomy in 2019? We propose to answer this puzzle by studying the colonial-era flag as a displacement device. The waving of the colonial-era flag is shown to induce non-linear temporal and extraterritorial displacements, as well as contradictory interpretations of Hong Kong’s core values, national sovereignty and cultural identity. The flag’s displacements are amplified against the contested colonial history of the former British enclave. Conceptually, this pragmatic definition of the flag moves beyond approaches that study flags as representations of a structure of symbolic meaning. The flag is neither an unimportant prop nor is it a free-floating signifier; its materiality elicits significant political effects. Methodologically, this translates into an exploration of the flag’s second-order agency. The old colonial-era Hong Kong flag, in combination with discourse and institutional arrangements, is shown to be integral to contentious politics. The flag and its displacements shed new light on a city uneasy with its past, dissatisfied with its present and uncertain about its future.