Lassie - Season 15 - Eps 22: Walden
Lassie befriend Patricia Prescott, who refers to herself as ""Walden,"" a free-spirited teenage girl, who has left home to live in the wilderness like her idol, Henry David Thoreau, after the young woman cleans up a picnic area. But both of them are endangered by aftershocks from an offshore earthquake.
About Lassie

Title: Lassie
First Air Date: 1954-09-12
Last Air Date: 1973-03-24
Status: Ended
Rating: 6.1/10 (from 65 votes)
Language: EN
Seasons: 20
Total Episodes: 591
Network: CBS
Genres: Action & Adventure, Drama, Family, Comedy
Production Companies: Unknown
Synopsis
Lassie is the pet of Jeff Miller, an 11-year-old farm boy. The two become best friends and enjoy family adventures in the American countryside, teaching each other about love, nature and commitment.
Cast

Hugh Reilly
Paul Martin

Josh Albee
Mike Bishop

Larry Pennell
Keith Holden

Larry Wilcox
Dale Mitchell