Two retired women, Nina Dorn (Barbara Sukowa) and Madeleine Girard (Martine Chevallier), have been secretly in love for decades. Everybody, including Madeleine's family, thinks they are simply neighbors, sharing the top floor of their building.

They come and go between their two apartments, enjoying the affection and pleasures of daily life together, until an unforeseen event turns their relationship upside down and leads Madeleine's daughter to gradually unravel the truth about them.