Disney musical about Mother Carey, a Boston widow, and her three children who relocate to Maine from their previous home. Their new home is a run-down old house that Postmaster Osh Popham helps them move into and repair. It is not completely deserted, however; the property's owner, a Mr. Hamilton, is a mystery figure who is now gone in Europe, but Osh tells them that he will not object to them staying there because he will not be returning home for a long time. Before an unexpected visitor turns up, the children and a cousin who has come to live with them go on a series of adventures together.