When widowed Margaret Carey (Dorothy McGuire) gets into money trouble, her teenage daughter, Nancy (Hayley Mills), devises a plan to cut costs. She writes to Osh (Burl Ives), the caretaker of an estate in Maine, and gets permission for the family to rent it for a song, with one catch -- the vacationing owner, Tom Hamilton, must be none the wiser. Though the Carey clan spends a carefree summer fixing up the big yellow house, Nancy fears that Hamilton will arrive and spoil the fun.