Far away from their native France, two men are in trouble in a Mexican town. One is a gentle missionary monk, Brother Benoît, the other is a tough stubborn boxer named Antoine Capella. Brother Benoît has saved a chimp he calls Mookie and who has become his pet but the trouble is that it is a talking monkey, which is the reason why a groups of scientists want to take it away from him. As for Capella, he has refused to lose a rigged fight and now a gang of badmen are after him to punish him. When the two men are forced to leave the town, they decide to travel together to Mexico.