During an awesome vacation at the Grand Canyon, Timmy's mule train descent down the canyon is disrupted by Lassie and later Timmy is helped by a befriended blind man and Lassie when Timmy is stuck on a path off the rim.

Cully inherits a famed tracking bloodhound whose senses Timmy discovers are failing but is loathe to disillusion Cully even when the dog is called to track a hobo thought to steal Ruth's full wallet which has really been pilfered by a crow.

Lassie is blamed for attacks on animals on area farms when a collie gone berserk due to a brain injury finds its way into the vicinity.

Timmy want to enter an different type of animal in the pet contest so he decide to capture a badger which lead to trouble for Timmy.

After a police dog and policeman befriended by Timmy and Lassie are shot by a bank robber, the dog on the loose becomes aggressive to the point of attack and might be killed by authorities except the dog is gentled by Timmy and Lassie.

Lassie is unable to follow the rules during a coon competition and, being thought mean, is barred from a swim competition which decision is reversed but Lassie loses because she saves the life of an struggling old dog.

During a dry spell, local farmers set traps to catch animals down from the woods to feed on farm crops which traps Cully springs as dangerous thus the farmers want Cully declared incompetent so Timmy wants Cully to reset the traps.

Timmy begins to feed a doe that has fled a fire in the woods just prior to hunting season and tries to capture the deer against the orders of Paul and Ruth but puts the deer in further danger.

When the fire chief's Dalmatian is killed at a fire, Timmy loans Lassie to the chief for during the day but Lassie becomes enthralled with the fire engine and fire chasing to the extent she ignores Timmy.

When Timmy undertakes breeding white rats to sell to a university veterinary researcher to raise money, the rats begin to destroy the farm crops.

Timmy fails to obtain a service dog for a blind boy (Joey) so the boy will make friends and then offers Lassie to the boy but the Martins and the boy's mother introduce Joey to a camp for blind children.

Lassie eschews a kitten given to her by a neighbor to compensate for not having puppies taking instead a mountain lion cub for which the mother comes looking.

A pair of men steal dogs for ransom until they lock up Lassie after stealing Lassie with their vehicle at which time Lassie frees the stolen dogs and alerts the law.

An illegally entered Mexican boy found injured by Timmy places the Martins in legal jeopardy as both Timmy and the Mexican boy struggle with doing the right thing.

When Pearlie Mae Yochim and her son Billy Joe, grieving over the loss of his dog and his father, visit the Martins on Christmas Eve,the boys rescue a man from under a sleigh and then find gifts in the Martin's yard including a puppy.

Cully foists a mischievous escaped parrot on Ruth as an ostensible birthday gift and will not take it back until Cully learns that there is a reward involved.

Lassie grieves mightily when a raccoon she has befriended as a companion while Timmy returns to school after summer is killed by a careless speeding teen driver.

Timmy raises for a 4H competition a sheep that he is given by a truck driver for helping the driver retrieve a flock and then has trouble persuading a sheepherder that the sheep is his when it mixes with the man's flock.

A colt Timmy finds after a forest fire and wants to keep must be auctioned by the county and, when it appears Timmy will lose the bid, Washburne puts up money on the condition Timmy will house but then the mare comes looking for the colt.

Disobedient Timmy hikes in the woods alone because his hiking partner is sick and is knocked unconscious after slipping down an embankment as a forest fire starts.

Timmy and Paul's nephew Richard find a trapped falcon which Richard, a cadet and falconer, instructs Timmy to train and, when it is learned that Timmy is too young to keep a falcon, the falcon is donated to the Air Force Academy.

After Mr. Grisby, a railroad worker and friend of Timmy, is injured, Timmy offers to take care of Mr.Grisby's pet chimpanzee Casey while he recuperates.

Lassie is locked into transport trailer while Paul is selling the farm crop at market in Capitol City and, when the truckers open the trailer over 600 miles away, panicked Lassie flees into nearby woods.

While Paul and Timmy search for Lassie, Lassie still lost continues her journey escaping several dangers and is taken in by an hunter who treats her wolf bites and feeds her from his larder.

Timmy grows increasingly despondent at Lassie's absence so that he is unable to accept Cully's puppy while Lassie instinctively forges ahead toward home and arrives just as Timmy has lost all hope.

When Cully and Timmy attend the Capital City Dog show, they are given free perks and accommodations because Lassie is mistaken for an expected to attend champion dog but the promoter is not peeved as Lassie has often saved embarrassment.

Paul attempts to solve the problem of a beaver dam blocking area irrigation by trapping the beavers for relocation but Lassie's fondness for beaver causes Lassie to spring the traps while Paul dissuades a neighbor from shooting the beavers.

An eagle that Timmy and Lassie rescued from a coyote trap helps save Lassie's newborn pups from a coyote.

When the assessor loses his entry book prior to arriving at Cully's, he threatens to alert the citizens that Cully's bloodhound has no sense of smell unless Cully finds the book which is found in a bear cave by Lassie or the bloodhound.

Timmy obtains an unwanted German Shepherd to give to Miss Hazlit's uncle, a disabled in the line of duty police dog trainer, and then finds that the dog's deafness prevents training but Doc Porter does a corrective operation gratis.

Timmy trains a mixed breed of dogs for a junior sled race entered with some resistance from Paul and Ruth and then makes the mistake putting in the lead a hunting dog which goes off course when distracted by a rabbit.

After a pensioner Timmy has befriended is hit by a car when getting his check in town, Lassie brings his little dog from the man's cabin deep in the woods to the hospital in an attempt to revive the pensioner from a coma.

Timmy's and Cully's efforts to impress upon a forestry official the need to declare a certain section of forest a wildlife refuge in order to prevent the construction of the road backfire with sometimes hilarious outcomes.

Timmy and Lassie save a premature calf of a heifer Timmy is tending while the surly owner Mr. Tate is away and, when Tate wants to send the calf to slaughter, Timmy persuades an attorney to sue for possession of the calf.

Cully's treasure hunting friend foist on him a small elephant which Cully is unable to contain and prevent from damaging the Martin farm and other property in the vicinity.

An animal trainer permits his tiger to swim in the fishing hole at which time it flees at Lassie' s bark and terrorizes the Martins while Sheriff Miller's posse is on the hunt and the trainer attempts to prevent the animal's destruction.