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.

While on a rafting trip throught the mangrove swamp, Sonny and Skippy come to the aid of a boy who has run away from his step-father while on a camping trip.

At home alone during a violent rainstorm — and nervous about radio reports of an armed bandit on the loose — Sonny and Clancy are surprised by a suspiscious visitor.

Sonny finds a man chopping down trees in Waratah National Park and when Sonny tells him it is illegal, the determined man insists that he owns the land. Matt Hammond has received word from Jerry of a bulldozer clearing land in the Park, and Mark radios in from his patrol boat that someone is building a fence down by the river. It transpires that "Honest Jack", a slick operator, has been selling blocks of land in Waratah National Park. For his final scam he tries to sell off Ranger Headquarters as an 'ideal home'.

A spoiled young violin prodigy, and an old family friend of Clancy's, insists on acquiring a baby koala but Skippy saves him from losing his life in the attempt.

A school for stunt men moves into Waratah National Park and Skippy, without needing any stunt lessons, saves their injured teacher.

Sonny discovers two dead possums in their tree trunk home and Matt is disturbed by the number of dead animals that have been found in the bush over the last three days. When Skippy is poisoned and almost dies, Matt calls in Veterinarian Officer John Manson. A poultry farmer with a grudge against Matt is responsible and Matt tricks him into revealing his guilt and the location of the poison.

Skippy sees a large truck from which a valuable thoroughbred mare escapes from the man who stole her. The horse finds temporary refuge with Sonny in Waratah National Park.

Matt Hammond is expecting a visit by a man to assist with blowing up an abandoned mine in Waratah National Park. The man turns out to be an old army buddy, Toby Boughton. Later, following an accidental detonation caused by a wombat, Matt and Toby are trapped in the mine which is slowly filling with water.

A young National Service deserter risks recapture to look after Sonny after he is injured in a rockslide.

Mark and Jerry go to investigate when Clancy notices someone lurking near the helicopter hangar. Jerry is astounded to find someone he has known since childhood. His friend, involved in an armed robbery and with a bloodied bandage around his head, convinces Jerry he is innocent and asks for refuge in Waratah National Park.

Sonny and Skippy see a flying saucer but the story is difficult to believe without seeing Sonny's photographic evidence — which he has lost. However, that doesn't stop the story from making the news, bringing a reporter out to Waratah National Park to chase down the story.

An old gypsy woman takes her revenge on Head Ranger Matt Hammond and his boys in a way that proves more embarrassing than harmful. Even Skippy is powerless to prevent the trick.

The Great Carl, an itinerant puppeteer who is camping in the Nation Park, is jealous of his talented young assistant. A puppet show is held at Ranger Headquarters to raise funds for the RSPCA.

Sir Adrian Gillespie arrives at Ranger Headquarters with news that Skippy is to be sent away to Sydney for a long-term scientific study to determine what makes her the world's smartest kangaroo. To avoid losing his friend, Sonny sets out to illustrate she's anything but.

In Matt's absense, an inspector from the Department of Civil Services arrives to evaluate operations at Ranger Headquarters. His strict by-the-book manner creates trouble for everyone and his panic during a crisis has near fatal consequences.

Clancy's music teacher stops by Ranger Headquarters to share her concerns with Matt about Clancy's recent change in behaviour. Mark convinces Sonny Clancy is living a double life and is being blackmailed — just like in Sonny's novel. While Sonny waits to catch the blackmailer, Matt follows Clancy in Sydney and discovers the truth.

The National Park must be closed to the public after a number of animal traps are found. A recently released prisoner working with local miscreant Ben Schuyler is responsible but it is not just the animals that fall victim to the traps.

When Sonny and Skippy help an attractive young scientist in her research work on sharks, only the last minute arrival of Jerry and Mark in the Ranger helicopter can save them from a school of maneaters.

Clancy thinks no one has remembered her birthday unaware that Mark has been planning a surprise party. Matt and Clancy run aground in the Ranger boat and nearly miss the party when they must walk back to Ranger Headquarters.

As Sonny urges his brother on, Matt plays along with Mark's plans of going on an around-the-world bicycle trip with a friend realising there are enough obstacles to halt the trip without him putting his foot down.

Sonny finds an orphaned baby wombat and brings it back to Ranger Headquarters where it runs amok. While Sonny goes in seach of the mother, Mark and Clancy must help with Sonny's exams and Matt calls from Sydney is need of some important paperwork.

A professional woodchopper practicing illegally in the National Park solves a problem for Jerry by helping him and Mark clear land for an emergency helipad. When the axeman's competition sabotages his car in an attempt to prevent him from competing, Skippy comes to his aid.

Two high-altitude hot-air balloonists bail out over the Waratah National Park. With the pair at Ranger Headquarts, Sonny and Skippy find the bolloon and manage to get airborn. As the balloon drifts out over the ocean, Jerry and the others pursue.

When Sonny and Skippy discover a number of wild horses in the National Park, Matt calls upon a national champion rodeo rider and his brother to round up the herd before they can damage the park.