Pinky (Jeanne Crain) is a black woman so fair-skinned she was able to pose as white throughout nursing school. Newly graduated, she flees south to visit her grandmother (Ethel Waters) after a doctor, unaware of her true ancestry, proposes to her. Unsure how to react, she looks to her grandmother, who warns her that only trouble will come of an interracial marriage. Pinky agrees and instead stays to help her grandmother care for an elderly, rich, and fatally ill white woman (Ethel Barrymore).