As Seoul undergoes rapid redevelopment, a network of volunteers is racing against time to rescue street cats. These rescuers rely on hyperlocal knowledge—details of cat colonies and individual animal habits—that isn’t found in official city plans. This essential information, accumulated over years by residents, is disappearing as neighborhoods are demolished. The process highlights a critical gap in urban planning where the impact on vulnerable animal populations and the value of community expertise are often overlooked. Rescuers document cat locations, health, and feeding patterns, creating unofficial maps vital for successful capture and rehoming. This work underscores the broader loss of intimate knowledge of place that accompanies large-scale urban renewal projects. Ultimately, the fate of these cats serves as a poignant symbol of the disappearing character of Seoul’s neighborhoods.