Twins Jean and Jo Weston are fifteen-year-old country girls who are just finishing their first year at boarding school in Melbourne. They receive bad news from their father: due to drought the farm at Emu Plains is struggling, and next year they will need to stay home and help around the property. They will also be required to tutor their little brother, Billy.

But just before they leave for home, Helen Forester, their school captain, makes a suggestion. Her little brother Rex will need looking after during the next year, and Emu Plains might be just the place for him. Helen says that her wealthy parents, who live overseas, would be willing to cover any expenses and Rex could be an ideal chum for Billy. The girls conclude an arrangement with Mrs. Forrester, but without telling their parents.

The scene is set for a tumultuous return home and a tremendous battle with the ongoing drought, a common feature of rural life in Australia.