After a ten-day Hawaiian vacation, Joanna Drayton (Katharine Houghton) returns to her San Francisco home with John Prentice (Sidney Poitier), her brand new fiancé. Although he's a successful doctor and a Nobel Prize candidate, her parents, Christina (Katharine Hepburn) and Matthew (Spencer Tracy), are taken aback when they discover John is black. While he quickly wins over Christina with his charm and intelligence, Matthew is more hesitant. And as John's parents also have their doubts over the impending marriage, the good doctor certainly has his work cut out for him, as he won't marry Joanna unless there's unanimous parental consent.