Roon is a cacheme, an organic human born of inorganic human extravagance. Her memory erased, she has only one clue to her past: her name. No longer of use to the people who created her, she wakes up in a glass box in a room full of girls in glass boxes on an airship, far away from the people and places that formed her identity, her past. Bukef is a hull-part-beast, part-war-machine. Hulls are built to bond with soldiers, their wicks, for life. But Bukef and Roon form an immediate attachment; each seeing something in the other that they understand. During an unexpected attack, Bukef saves Roon, and she becomes an unlikely wick, not a soldier at all, not built for war. Their bond runs deep. Together, they have to outsmart their vindictive creators and try to find the place that Roon once called home.