The heroic champion of Nimruz, Rostam, having taken leave of his white-haired father Zal, spurred his legendary steed Rakhsh toward the perilous realm of Mazandaran. Riding relentlessly, he collapsed two days' journey into a single day and paid no heed to the gloom of night, treating dusk as dawn while Rakhsh devoured the miles beneath his thunderous hooves. When hunger gnawed at the champion's mighty frame, he chanced upon a vast plain teeming with wild asses. Spurred by Rostam's command, Rakhsh overtook the swift prey with ease. With practiced deadly grace, Rostam cast his Kianian lasso, entrapping a formidable wild ass, brought it down, and slaughtered it like a roaring lion. Striking sparks from his iron arrowhead, he ignited a fiery pit of brushwood, skinned the beast, and roasted it whole. With the earth as his table and the open fire his hearth, he feasted until satisfied.
Leaving Rakhsh unbridled to graze freely in the lush meadow, Rostam fashioned a bed amidst a thick reed bed, treating this domain of unknown peril as a haven of rest. Yet that reed thicket was the lair of a terrifying lion—a beast so ferocious that even wild elephants dared not cross its domain. As the first watch of the night passed, the ferocious predator returned to its home, only to discover an elephantine charger standing guard over a sleeping giant. Reasoning that it must first slay the steed to prevent the rider's escape, the lion charged forward like leaping flame. But Rakhsh, vigilant and fierce as a boiling cauldron, reared high on his hind legs, slammed his forehooves into the beast's head, and sank his razor teeth deep into its spine. With brute, wild force, Rakhsh dashed the lion repeatedly against the stony earth until it lay torn into pieces.
When Rostam awoke and beheld the dreaded king of beasts shredded upon the ground, he turned to his faithful steed with a mixture of awe and stern admonition: 'O watchful champion among steeds! Who permitted thee to do battle with a lion alone? Hadst thou perished in its claws, how could I have carried this heavy mace, helmet, and lasso all the way to Mazandaran on foot? Why didst thou not wake me with thy thunderous neigh?' As the radiant sun crested the dark mountain peaks, Rostam rose from his sweet sleep, wiped the dust from Rakhsh's glowing hide, strapped on his saddle, and praised Yazdan, the Bestower of Good, before embarking upon the road once more.