The New Adventures of Lassie - Season 2 Episode 5 A Wild Encounter
Overview: After Lassie helps a young horse-rider to control her unruly mustang, Zoe and Sarah take her in as the horse rests. But when two brothers turn up in the valley in search of their stolen mustang ,Zoe realizes it's her new-found friend, who has now suddenly disappeared. Lassie encourages Zoe to listen to her heart and our heroic trio sets off in search of the girl.