Constructed solely for war, sayabito are fearsome human weapons who are tightly bonded to those who wield them. In the wake of a great war, fiery and impatient Rivia and her willowy, cautious partner Kuifa roam the land in search of sayabito who lost their wielders in the conflict, in order to register and protect these vulnerable sayabito before they wither away or are exploited. Though Rivia and Kuifa frequently exasperate each other with their clashing approaches, they share one common goal: to carve out a life in the peacetime for which they, and others like them, were never meant.
A date with May turns deadly when Rivia is suddenly cornered by the enemy and given a choice—to return to her former addo or die. And ignorant of the danger they’re in, Kito and Swito take in a stranger they find out in the bitter cold. Their acts of kindness help the sayabito recover, but can they warm his heart enough to quell the killer voices in his head?