O Galo Missioneiro tells the story of Olívio Dutra, former mayor of Porto Alegre and former governor of Rio Grande do Sul (Brazil). In a time of hatred and intolerance, the documentary follows the daily life of the tireless militant Olívio, who continues to act and fight for a society where people are protagonists, not objects of politics. Made in an independent and militant way, the film rescues the good examples of politicians and managements for a more humanized world.