Set in the fictional Waratah National Park (NSW), the Skippy series focuses largely on the adventures of a young boy, Sonny Hammond, and his intelligent pet kangaroo, Skippy. Sonny is the youngest child of Head Ranger Matt Hammond. Matt was left a widower in his early forties when his wife Mary died not long after Sonny was born. Other principal characters are Sonny's older brother Mark, Flight Ranger Jerry King (the park's helicopter pilot), and Ranger Clancy Merrick, the teenage daughter of another park ranger.