Mathias Gold is a down-on-his-luck New Yorker who inherits a Parisian apartment from his estranged father. But when he arrives in France to sell the vast domicile, he’s shocked to discover a live-in tenant who is not prepared to budge. His apartment is a viager—an ancient French real estate system with complex rules pertaining to its resale—and the feisty Englishwoman Mathilde Girard, who has lived in the apartment with her daughter Chloé for many years, can by contract collect monthly payments from Mathias until her death.