Sonny has been placed in charge of an automatic recording unit deep in the bush of Waratah National Park, supervised by his father, Chief Ranger Matt Hammond. While servicing the box, Sonny finds an Air Force pilot who has ejected from his airplane. In trying to rescue him, Sonny slips and becomes trapped on a cliff face. Skippy goes for help and returns with Matt who rescues Sonny and, with help from Mark and Jerry in the helicopter, the pilot as well.