Since the Night of Endless Swords, a bloody battle the Kings of Sharakhai narrowly won, the kings have been hounding the rebels known as the Moonless Host. Many have been forced to flee the city, including eda, who discovers that the King of Sloth is raising his army to challenge the other kings' rule.

When eda finds the remaining members of the Moonless Host, now known as the thirteenth tribe, she sees a tenuous existence. eda hatches a plan to return to Sharakhai and free the asirim, the kings' powerful, immortal slaves. The kings, however, have sent their greatest tactician, the King of Swords, to bring eda to justice for her crimes.

But the once-unified front of the kings is crumbling. The surviving kings vie quietly against one another, maneuvering for control over Sharakhai. eda hopes to use that to her advantage, but whom to trust? Any of them might betray her.

As eda works to lift the shackles from the asirim and save the thirteenth tribe, the kings of Sharakhai, the scheming queen of Qaimir, the ruthless blood mage, Hamzakiir, and King of Swords all prepare for a grand clash that may decide the fate of all.