Dr. Alexander Stark is determined to have Skippy for his private zoo. When Matt Hammond refuses to sell at any price, Stark has two of his henchman steal the kangaroo and she begins a tense series of adventures to find her way home.

With Sonny Hammond as a hostage and a rifle pointed at Head Ranger Matt Hammond's head, bank robber Keeler forces Matt to drive him from Waratah National Park to keep his rendezvous with accomplices.

Sonny and Skippy become guides for foreign children stopping at Waratah National Park while touring Australia.

Sonny travels to Sydney to persuade his friend Mr Trundle (alias Miles Vincent Archer) to return temporarily to his desk as chairman of a vast corporation and reverse the board's decision to despoil Waratah National Park by drilling for oil.

When Aunt Evelyn comes to Waratah National Park determined to persuade Head Ranger Matt Hammond that he should put his younger boy Sonny in boarding school in Sydney. Sonny and Skippy save Evelyn from death by drowning and Sonny is saved from a fate he'd consider worse than death.

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.

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.

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.

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.

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.

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.

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.

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.

Mark begins training so he can participate in the Waratah Athletic Association's cross-country marathon that is being run through the park. Despite taking a commanding lead in the race, in no small part due to a route mix-up, Mark isn't the first one to bound across the finish line.

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.

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.

Jerry is asked to be the Best Man at a friend's wedding but gets caught up chasing two hooligan's in a stolen motorboat and rescuing a stranded hiker.

Jerry and a visiting ornithologist, who herself is not what anyone was expecting, nab two men poaching wild birds in Waratah National Park.

Two botany teachers hiking in the National Park ignore Sonny and Jerry's warnings and procede into a dangerous area only to run into an emergency when one is bitten by a snake. Skippy brings the snake back to Jerry who searches out the women to inform them the snake is harmless.

A shy and unassuming young woman visits Clancy at Ranger Headquarters. Mark makes an effort but Jerry goes out of his way to avoid spending time with her until Clancy, with the help of a friend, transforms her for a beach party.

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.