"Zohak" is a Persian legend about a tyrant whose reign of terror is enforced by two serpents growing from his shoulders (Byur and Bur), which demand a daily tribute of fresh human brains. The oppression continues until the tyrant's agents execute six sons of the blacksmith Freydun. In response, Freydun turns his humble leather apron into a revolutionary banner and leads the oppressed workers in an uprising to overthrow the tyranny.