On the borders of Northern Wei, storms brew beneath the snows of the Six Garrisons. Scout Helan Tuo escapes death in an ice coffin on the Luo River, where he witnesses a bizarre Buddhist ritual: three hundred warrior monks in formation, and a rotting corpse gripping a shovel inside an iron coffin. He uncovers records showing that the men of Huaishuo Garrison were sold off to pay for the transport of military supplies, hiding the truth of a collusion between the Bureau of Military Supplies and the Yuwen clan of the Rouran. In an ambush at White Wolf Ravine and an iron coffin beneath an icy lake, he finds a bow stave of zhe wood, the Fourteenth Year of Taichang Military Supply Allocation ledger, and a bloodstained fragment of a star chart. Together, they reveal the truth: the main beam of the ancestral shrine was stolen, and the flesh and blood of the men were forged into the Rouran's blades.
In the dungeon, Lu Shen uses his own blood and flesh to draw a map of beacon fires. A map of the waterways and the mark "fit for slaughter" appear inside a rotting corpse, exposing every vital artery of the Six Garrisons' defenses. In the underground palace of Yongning Temple, Huijue uses the bones of seven hundred people to forge fake Buddhist relics, plotting to sacrifice them to the Rouran royal court. Helan Tuo activates his ancestors' flood-control sluice mechanism and reverses the bloody cycle, sweeping the corpse puppets, warrior monks, and Rouran vanguard into a whirlpool together. The sluice gears at the White Road Gorge thunder into reverse as a severed hand and the core component are put back in place. Wang Yanli's qilin armor collapses along with the canal stele, exposing the Buddhist relics and the crucial sluice gear.
At last, Helan Tuo uses a military talisman from the star chart to awaken the underground palace's bronze sluice mechanism, and a glass Buddhist shrine topples into the Luo River. The seven hundred "Buddhist relics," the inscriptions on the gold ingots, and the remains of military supplies are ground to dust in the flood. The blood-soaked Canal Dredging Register and A Zhao's broken hairpin in his arms bear witness to the bloody truth: the bones of the men of the Six Garrisons were forged into tribute for the Rouran and turned into lamp oil before the Buddha. As the Luo River carries the wreckage eastward, new plowshares and tender green wheat shoots rise from the scorched earth, as if heralding a new beginning after the wronged have finally been vindicated.
