The story takes place in a district of Paris that has been transformed by major disasters during the 21st century. It shows how society is organized around desirable and sustainable housing projects. The plot revolves around the integration of new residents, the Huangs, into a community residence in which services between people harmoniously structure daily life. The arrival of these new residents, survivors of the collapse of their building in Mongolia, which they were able to leave thanks to the Migration and Solidarity Program, disrupts the well-oiled organization of a "model" neighborhood in terms of social cohesion and environmental quality.

But why do we never meet Quinn, the Huangs' child? What lessons can be learned from solving the enigma?