A "new" Lassie (once again, a male collie in drag) starred in A Challenge to Lassie, MGM's fourth entry in their series based on characters created by Eric Knight. This time, Lassie is plunked into the plotline of William Ludwig's novel Greyfriars Bobby (remade by Disney under its original title in 1963). In 19th-century Edinburgh, crusty sheepherder Jock Gray (Donald Crisp) rescues a puppy and raises it into a champion sheep dog. When Gray is murdered by rustlers, his faithful collie keeps a night-and-day watch over his late master's grave, despite local laws banning the presence of unleashed canines. The rest of the film is a battle of wills between kindly innkeeper John Traill (Edmund Gwenn) and by-the-book constable Davie (Reginald Owen) over the dog's well-being. A romantic subplot is capably handled by Geraldine Brooks and Ross Ford, both of whom went on to healthy character-actor careers.
by Hal Erickson synopsis