While Lassie is visiting one of her puppies that she placed with a rancher's son, she accidently falls down an abandoned shaft. It takes the combined efforts of several people, all of whom have one of the collie's puppies, to help rescue her.
TRIVIA This was the second to last Lassie episode before the series was cancelled by the major public network, ending 17 years of Lassie which was one of the longest running series during that time. All the following episodes were part of a syndication package only shown on cable TV. That syndication only lasted two seasons before it was cancelled.