Stilltown is set in Gravines, a small industrial town in the 1990s, marked by the closure of the MTLK factory, which had been an economic and social pillar for generations. Clémence Rosier, born into the bourgeoisie and heir to the factory, sees her world collapse when her son Benjamin disappears. When the child's body is found and the investigation fails, Clémence sinks into despair. Three years later, as she prepares to leave town with her husband and daughter to turn the page, another tragedy turns everything upside down: Stella, Ben's former best friend, vanishes. This time, Clémence refuses to remain a spectator. Convinced that the two cases are linked, she teams up with Antonio D'Ambrosio, a laborer and once the main suspect in her son's death. Together, they must face their prejudices, unearth the town’s buried wounds, and confront a threat that has never gone away.