An invasion of sports cars threatens the life of protected fauna in Waratah National Park, but when Matt leads a rescue squad to save the life of a driver pinned under his car in a serious accident, the rally organisers gratefully decide on another venue.

Mark is unhappy when his father, Matt Hammond, tells him to accompany a marine biologist who wants to collect underwater specimens. But his misery turns to delight when he discovers that the marine biologist is a spunky young woman. The two of them quickly find themselves having to rescue Skippy and an unconscious Sonny from an out-of-control speedboat.

Clancy's time with the Hammond family appears to be at an end when she sits her final music exam. Her departure is ensured when she wins a prestigious scholarship to study music in London. Sir Adrian asks Matt to select a Ranger to go oversees to work in Sherwood Forrest.