Cecil secretly leaves Keph with Ned Flan'Deres, Lendo Malorian, Cass, Trash King, Snake Eye Joe, and Th'Marck, while an eighth unidentified traveler follows them into the darkness. Meanwhile, the Harbingers reach a cave on the southern shore of the polluted Iron Lake and survey the Chained Fortress: three concentric circles sealed behind a colossal mountain wall, with the outer circle functioning as a vast war machine. Inside the cave, they find a traumatized young man who escaped the fortress with his family aboard a cart from Vilk. The Chain prevented them from traveling beyond the nearby road, his older brother was recaptured, and his parents starved while hiding with him. Torrin's lesser restoration returns the survivor to awareness, and he warns the Harbingers that the outer circle contains furnaces where enslaved workers build weapons containing living people, while those not used for the war are taken into the inner circles.

At the Shadow Claws' settlement, Helena convinces Bjork's mother, Bjor Kavaar, to surrender the key to Kethrick Voss's cell. Kethrick admits that he was attempting to siphon the Shadow Claws' magic when he was captured, gives his true name as Velric, and agrees to help Helena unite the clans under a freely chosen alliance. When the antlered Watcher from the forest attacks the settlement and tries to take Helena's light so it can return home, Velric dons his porcelain mask and drives the creature away with power stolen from the Watchers' masters. He then confesses that he intended to betray Helena and warns that the Kahren'Vare may not deserve her trust, but chooses her cause over his old patrons. Using a portion of Helena's light, Velric shatters his mask, severs himself from the Watchers, and transforms one of the cursed Shrykes into a blue hippogriff from Teldoroth. Helena and Bjork rejoin the others, but Helena's revelation that she destroyed the Helm of Skjold provokes a fierce confrontation with Bjorn over the symbol his people rallied around after the siege of Keph. Helena argues that the Skjold do not need a crown, Bjorn insists that he is not Skjold, and Ernan comforts the humiliated Bjork after his father throws him to the ground.

The reunited Harbingers fly to an eastern mineshaft beneath the Chained Fortress, survive explosive runes, kill its malnourished guard, and prevent an enormous undead amalgamation from escaping its cage. An elevator carries them into mines filled with silent laborers worked beyond exhaustion, many of whom have already died where they fell. Disguised with false chain marks, the group evades a Rusticulum foreman and passes several eastern tunnels sealed with skull-marked barricades. Helena senses a dragon within a mile, but the Harbingers follow Torrin's compass toward the final Crystallic fragment instead of freeing it. A second elevator brings them to the Eastern Foundry, where they bluff their way past Myles, a well-kept overseer who sends them down into the outer circle. Helena secretly remains behind and poses as an inspector. Myles explains that fear and trauma make victims easier to bind, that many enthralled workers are now irreversibly broken, and that some inhabitants are not controlled at all. As the others descend into a furnace district where thousands labor within Draxus Kael's war machine, Helena looks beyond the foundry and discovers the prosperous second circle: a place of white homes, art, culture, and affluent people willingly benefiting from the Chain.