Timmy and the other school children save money to buy stamps with the hopes that they win a plaque as a prize. However, the money is stolen from the school and Lassie tries to sniff out who the culprit is.moreless
Paul and Uncle Petrie try to find subjects for Timmy to take pictures of with his new camera. However, an unpleasant neighbor may dampen Timmy's fun with his hunting plans.
Lassie brings home a little dog that she has been secretly been feeding. However, the warm feelings Ruth has about this situation quickly sour when Timmy adopts a feisty race horse.
Timmy and Boomer borrow Uncle Petrie's charm to give them good luck for an upcoming school project. However, they lose the charm and Petrie starts to have a run of bad luck.
Timmy and Boomer collect rocks as part of payment for breaking a neighbor's window but the two begin to suspect the neighbor may in fact be a bank robber.
Lassie, staying at a neighbor's house while the family as at the county fair, is blamed for the damage done by Chipper, a chimpanzee being nursed by Mrs. Collins.
Timmy and Boomer are heartbroken when they find out Lassie's puppies are to be sold, so Lassie hides them in an old pen in the woods. But the mischevious babies get free.
Knowing Ruth hasn't had a new hat in four years, Paul buys her a lovely spring hat he discovers she was longing for, but Timmy and Lassie inadvertently ruin it while playing.
The Martins adopt a cat they find half-drowned outside the house, but the conniving cat, dubbed "Marmalade" by Timmy because of his color, immediately starts getting Lassie into trouble.
A breeder says Lassie may be descended from a famous show dog and urges Timmy not to let her run wild, so she must sit on the sidelines while Boomer's terrier Mike has all the fun.moreless
Asa Winkler, a conniving handyman, claims Lassie bit him and tore his pants to obtain odd jobs at the Martins--and arranges other "accidents" to stay on.
When Lassie keeps coming home with greasy muck on her legs, Timmy and Boomer investigate, and discover a pool of oil on their property. But Uncle Petrie's investigation of the pool proves to be his undoing.moreless
For a club project, Timmy and Boomer adopt a tree that was supposedly planted by Johnny Appleseed, then discover it is sleighted to be cut down to make way for a highway, so Timmy writes a letter to the President of the United States.moreless
Ruth, taking a woods shortcut on her way to a Grange supper and having to replace a flat tire, is caught in a trap set by a state hunter to catch a marauding cougar.moreless
The Army is conducting war games near the farm, and excited Timmy, Boomer, and their friends plan their own maneuvers. But it's no game when scout Timmy and his "war dog" Lassie wander into a live mine field!moreless
Timmy and Boomer want to be partners in a business, and, learning Paul is planning to spend $10 on ladybugs to help fight aphids in his apple orchard, are determined to find a cache of them Lassie discovered earlier. But the collie wants nothing to do with the itchy pestsmoreless
Several days before Christmas, Lassie is struck by a truck while saving a three-year-old girl and so seriously injured she needs a special veterinarian to operate on her
Tongues wag in the neighborhood after Lassie picks Ruth's ticket as a winner in a raffle for a piano--but the real loser is Timmy, who's forced to take lessons
Having seen sugar maples while taking Timmy on a nature hike, Uncle Petrie returns to the woods to investigate--and runs into two men holding bank president Robert Hanson hostage. Remembering that he taught Timmy smoke signals on their hike, he makes a desperate gamble while helping one of the criminals make a fire.moreless
Boomer is jealous when Timmy seems to prefer the company of his English visitor, Robin, and his little Cairn terrier Basil, so he and a classmate make fun of Robin's short pants and school tiemoreless
On a bird-watching expedition for school, Timmy sees a rare snowy egret, but no one will believe him. Finally a professor is dispatched to see if his report is true.
Timmy's plan to help his new friend Henry, who is afraid of dogs, backfires when Henry mistakes Lassie's extra attention as love for him and believes she wants to stay with him.