Lassie secrets home and befriends a pigeon in a cage belonging to a magician who Lassie believes is harming the pigeon because Lassie does not understand illusion.
Timmy and Lassie adopt two orphaned foxes after the mother fox is killed by a hunter dogs. But Timmy must face the realization that now that they are able to fend for themselves they must be freed in order for them to survive in the wilderness.
Timmy convinces his friend Andy that he would take care of his pregnant dog Sibyl while he goes to the city. But when Timmy and Sibyl are going to Timmy's home, a speeding car hit the dog who runs away injured and hide out in a abandoned unsafe mine which lead to Lassie rescue.
The wild animals nesting in Cully's barn moved by Cully and Timmy temporarily to an outlying shed pending demolition of the barn by the county continue to return to the barn so Timmy writes a letter to the newspaper to save the animals.
When Paul and Timmy arrive to pick up some goats Paul has bought, a goat is found dead from anthrax so Timmy, Paul, Weaver and Simms must struggle to keep the remaining goats in the rocky cliffs to prevent a valley quarantine.
Lassie and Timmy endeavor to accustom Chief Washburne's dog Smokey to fire department noises and commotion so Smokey might overcome his fears and become an authentic firehouse dog.
A boy who is part of a marginal father and son clown and novelty animal circus act persuades Timmy to leave home and join the circus as a partner in an act which will feature Lassie.
Lassie assists a champion Irish Setter that craves relief from the strict regimen of the show ring stowaway in the Martins pickup to the farm and the dog's owner is displeased with the dog's behavior and treatment at the farm.
After Timmy, without thoroughly searching for the terrier's owner, gives a terrier he has found to a neighbor boy despondent that his orphan status has displaced him from France, a pet shop proprietor comes looking for the dog.
Lassie receives a wound saving Cully from the shot of a careless deer hunter and the family must persuade a neurosurgeon temporarily in Capitol City to operate on a dog to prevents Lassie's paralysis from the bullet's movement.
Timmy helps a boy whose carelessness has resulted in paralysis to his Labrador retriever build a cart to allow the dog some freedom of movement but the boy's Labrador breeder father thinks the dog's destruction is best.
So that Mr. Washburne's fish will not be ineligible in a contest because Lassie found it, Timmy has to hide that Lassie can find large fish despite that he will be rebuked for creating a news story frenzy by telling Lassie's ability.
At the county fair Jake Hodges who has a hot air balloon befriends Timmy and Lassie, but when the hot air balloon start to drift away, Timmy becomes trapped in the balloon while trying to stop it with Lassie jumping in to save Timmy and together they drift away.
The hot air balloon with Timmy and Lassie is caught in tree branches in the Canadian wilderness and Timmy must now find a way down and to find water once they are on land.
Landing in the woods from the hot air balloon journey, Timmy must resort to his scout survival skills to find food and shelter, but is sidetrack when Lassie is attacked by a wild boar.
When Lassie developed a fever after being attack by a boar Timmy find a river to cool Lassie and is convinced that following the river in a raft he built will lead him to people for help.
When the raft Timmy and Lassie capsizes they become separated, Lassie is cared for by a deaf-mute Indian, while Timmy is reunited with his parents Lassie must find his way back to Timmy.
Learning that traditional bluebird nesting sites are declining, Timmy builds birdhouses for the area to preserve the species but the preservation project is imperiled when the local farmers use dynamite to combat a starling invasion.
Neighbors grow angry with Cully who has falsely warned them of an impending frost when he misinterprets strange animal behavior but Lassie helps Cully reinterpret the behavior as a coming twister so he must use Paul to spread the word.
A turkey farmer whose poults are being raided by an owl accuses of rustling a transient who has scavenged a chick that Lassie has caused the owl to drop.
Cully borrows from the Martins to enter a burro race at the county fair hoping to win funds to buy some land before neighbor Krebbs can but draws a puny, stubborn female only Lassie can handle. Meanwhile Krebbs locks Lassie in his barn.
A bag of pine cones that Timmy is assigned from his class by a forest ranger to collect for seeds to use in a flood break planting is washed away by runoff when Timmy leaves the bag in the woods because it is too heavy.
After Cully suffers a heart attack he worries about his farm, but Timmy offer to help on the farm with Lassie. Timmy encounters a gopher problem and uses a weasel to counterattack the problem but the weasel becomes a problem too.
An army dog that accidentally injures its trainer flees and follows Lassie home where its training is mistaken by a fearful Timmy and Ruth for unreasoned aggression.
Participants in a pigeon race Timmy has organized are very angry when the pigeons do not return because everyone is unaware that radar operating in the area has interfered with the pigeons' navigation.