Stranger in opulent silk robes, Kazem, sends hungry penniless Persian street rat Dastan on a caravan from Nasaf to Babylon, with a small box, in return for a large sum. Pursuit by royal guards and viper-carrying bullies seeking a reward leave the reliable messenger no choice. After delivery, twice the initial sum is promised, enough to set up the orphan in comfort for life. But the destination has a soldier dead from a dagger in his throat. Again acrobatic Dastan takes to the rooftops, his kingdom, fleeing with a price on his head.