It was shown as part of a retrospective on Spaghetti Western at the 64th Venice International Film Festival.
The townspeople mistake him for Ward Cluster, a former resident thought to have died in the Civil War.
Even Cluster's son, Sean, raised by an Indian chief named Gray Bear, thinks Barton is his father.
Tom Cherry, the most troublesome of the three brothers, is involved in dealings with the Mexican army.
Barton teams up with a wandering sheriff from Tucson and, in a final shoot-out, kills Tom.