Zahhak, reckless son of the good Arab king Mardas, is flattered by Iblis into an oath. Iblis digs a pit in the garden path, Mardas falls to his death, and Zahhak takes his father’s throne.
Disguised as a cook, Iblis feeds Zahhak the first meat: egg yolks, then fowl, then lamb and veal. As his reward he kisses the king’s shoulders, and two black serpents grow there. Returning as a physician, he prescribes human brains as their food.
Iran falls into disorder, and its chiefs go over to the Arab king Zahhak, who takes Jamshid’s throne. Jamshid hides for a century, is caught by the Sea of Chin, and is sawn in two. The poet reflects on the world’s treachery.
Zahhak rules for a thousand years. He takes Jamshid’s two daughters, Shahrnaz and Arnavaz, and each night two young men are killed to feed his serpents. Two pious men, Armayl and Garmayl, become his cooks and save one youth in every pair, from whom the Kurds descend.
Forty years before his end, Zahhak dreams of three warriors, the youngest of whom strikes him with an ox-headed gorz and drags him to Damavand. After three days of terrified silence, the Mobad Zirak tells him that Fereydoon, not yet born, will overthrow him to avenge a father and a cow.
Fereydoon is born. Zahhak’s men kill his father, Abtin, and his mother, Faranak, hides the child with the herdsman of the wonderful cow Barmayeh. When rumor spreads, she carries him to a holy man on Mount Alborz. Zahhak kills the cow and burns their house.
Fereydoon smashes Zahhak’s talisman, kills the Divs in the palace and takes the throne. He cleanses Jamshid’s daughters of the tyrant’s sorcery, and Arnavaz tells him Zahhak has gone to Hind, where he bathes in a vat of blood to cheat the stars.
Zahhak climbs into his palace by kamand and attacks, but Fereydoon strikes him down with the ox-headed gorz. Soroush forbids the killing. Fereydoon restores the order of warriors and craftsmen, then carries Zahhak to Mount Damavand and chains him in a bottomless cave.