Jock Gray (Donald Crisp) stumbles upon an ownerless puppy named Lassie and decides to raise the youthful canine as his own. They live happily together until one day Jock is robbed and killed while traveling, leaving Lassie all alone. Feeling a deep bond to her former owner, Lassie returns each day to his grave despite the efforts of Jock's friend John (Edmund Gwenn) to find Lassie a new home. Lassie's prospects become dire when the local sheriff detains Lassie, threatening to put her down.