Towards the end of the Shahanshah's reign, Sergeant Makvandi is assigned the commander of the gendarmerie station in a small town. A stern disciplinarian, Sergeant Makvandi tries to impose order at the station but, being as degenerate as his subordinates, he fails to re-store discipline. faced by rebellious crowds, he imposes martial law, but people outwit him by mailing to his address a forged letter which "promotes the sergeant and ends the curfew". Makvandi tries to intimidate a school teacher into writing a song which he wants the students to sing on the day his "promotion" comes into effect. But the teacher refuses to give in, for he and his students are preparing to sing a new song, the song of revolution.