Bobby, a sparky, silver-haired Skye terrier, adopts Auld Jock, a worn-out simple shepherd, as his master. Jock is let go by the farmer and dies in poverty, having suffered one winter too many.
The farmer tries to reclaim Bobby as a pet for his daughter, but the dog owes allegiance only to Auld Jock, guarding his grave in Greyfriars Kirkyard. His devotion changes the lives of those around him and ultimately the conditions of the poor in Edinburgh.
Bobby's loyalty is eventually rewarded, and he becomes a famous dog indeed!