Mathias Gold (Kevin Kline) 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 (Maggie Smith), who has lived in the apartment with her daughter Chloé (Kristin Scott Thomas) for many years, can by contract collect monthly payments from Mathias until her death. With no place to go, Mathias strikes a tentative lodging arrangement with Mathilde, instantly clashing with suspicious, lovelorn Chloé over his private dealings with a rapacious property developer, who wants to purchase the apartment. An uneasy détente settles in as the quarreling Mathias and Chloé come to discover a common ground of childhood pain and neglect. As they draw increasingly closer, Mathilde unveils a complex labyrinth of secrets that unites the trio in unexpected ways.