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.

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.

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.