In Nazi-occupied Holland in World War II, shopkeeper Kraler hides two Jewish families in his attic. Young Anne Frank (Millie Perkins) keeps a diary of everyday life for the Franks and the Van Daans, chronicling the Nazi threat as well as family dynamics. A romance with Peter Van Daan causes jealousy between Anne and her sister, Margot. Otto Frank (Joseph Schildkraut) returns to the attic many years after the eventual capture of both families and finds his late daughter's diary.