Ruth and Timmy, visiting the Grand Canyon, befriend a blind pianist with a unique outlook on life who helps Timmy after he is angered by Lassie's behavior when she follows him on a mule ride and he's forced to turn back.

Timmy and Lassie discover the sad truth about Relentless, Cully's new--and much bragged about--dog: he's lost his sense of smell. The truth might have remained secret had not the money earned in a church fundraising drive gone missing.

The Gardners, the Martins' new neighbors, accuse Lassie of killing their cat and attacking their sheep, but Lassie knows there's a strange collie in the area.

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.

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.

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.

Lassie, lonely when Timmy returns to school after a vacation, befriends a raccoon. She is devistated when the raccoon, whom Timmy named Melonhead, is run over by young drag racer Johnny Sexton.

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.

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.