Timmy finds an injured Lassie after she cleverly escapes from the junk yard of her neglectful owner, Hollerin' Hank Cranforth. But just as Timmy and Lassie become instant friends, Hank returns to claim her, leaving a despondent Timmy.

Only Lassie can set things right when Timmy disobeys his mother and takes a precious heirloom to baseball practice.