Flash, Barin, Aura and Thun are brought to Sky City before King Vultan of the Hawkmen. He is elated to find several pieces of royalty now under his control, Princess Aura in particular; he plans to marry her, and force Ming to share his power. The others, he has no such feelings for, and they are subsequently sent to work in the furnaces. Down here, Aurium is burnt, the first step in a process that ultimately keeps Sky City afloat - but the work, heat and radiation are such that Vultan goes through workers very quickly indeed. Flash makes a valiant escape effort, but he is caught and subdued, now with a device on his ankle which can be used to shock him when he steps out of line. Barin, however, proposes that their captors may have just given them their way out.
Back in Mingo City, Dale resides among a great many exotic women in Ming's harem, but her thoughts concern only Flash, wondering if he is still alive. Through a secret passageway (the palace has many), Zarkov enters her quarters, such as they are, with news on that front: Thanks to a meeting with Ming, he is able to tell her that Flash lives, albeit as a prisoner of Vultan, something even Ming admits he would only wish on his worst enemy. Worse, Ming is about to launch an all-out attack on Sky City in order to get his daughter back. Still, he is sure that Flash will find a way out. As he is forced to leave, a guard approaching, Zarkov declares that Ming, intelligent and ruthless as he is, can be beaten.
Thun manages to get the device off of Flash while the guards aren't looking and places it on a pile of Aurium. With that accomplished, they incite the workers to revolt, led by Flash himself. The guards activate the device, sitting on a pile of the unstable mineral, and cause an explosion, damaging the systems that keep the city in the air. In the chaos that follows, Flash, Barin and Thun escape into the open city, just as the attack begins. A spectacular battle follows between the forces of Vultan and Ming, but it soon becomes evident that Vultan is outmatched. Parts of Sky City are destroyed, many Hawkmen perish, and it isn't long before they force their way into Vultan's throne room, with Ming personally striding in and reclaiming his daughter.
The prisoner freed, he orders his Metal Men to finish Vultan and what remains of his forces. Before they can, Flash and his companions intervene, helping the Hawk Men fight back. Finally, Flash fries one of the robots with a bucket of water before it can execute Vultan himself. Vultan is spared, allowing him to lead an evacuation of the city, streams of Hawk-People flying away as the rest goes up in smoke. Ming, watching from his palace, decides that the damage is superficial; he will add it as another jewel in his "crown of conquests."
Having gathered on a cliff some distance away, Flash, Barin, Thun and now Vultan have other ideas. Having each felt Ming's wrath, they choose to put aside their differences and work together, vowing to return every bit of trouble Ming has caused them back to him. Ming, watching their meeting remotely, begins pondering his own next move...