Gumercindo is a simple man who sees the daughter become pregnant of the son of its boss. Determined to demand that his grandson have a father, he joins neighbors to seek justice in his own way.

Inácio Pororoca is responsible for the local mail in an old west town. One day there comes bandit João Bigode, who kills the sheriff and puts Inácio on his place, just for fun. But Inácio takes his post seriously, and soon the bandits realize they've made a mistake.