Colomba Legend | The return of Vito Colomba in "four jackals in Malopasso"

Colomba Legend’s story develops exactly twenty years after the events related in “Quattro Carogne a Malopasso”, a western movie made by Vito Colomba between the 80s and 90s. The main characters are the historical characters’ sons: Parker and Nelson. After the wrongdoing done by the bandit Parker, the Custon City’s dwellers are obliged to face up a new threat: four masked bandits who make crimes one after another, terrorizing the city. Bill Nelson Junior is sure that the responsibles are the four Parker’s sons, abandoned twenty years before the day of their birth, in front of a Friary. Bill doesn’t like the sheriff’s actions, so he gets on their trails and fights for the truth, in order that it comes out once and for all.
Are they the real responsibles of these savages crimes? Or might there be something else?