The Shadows, a noble family defined by their jet-black appearance and habit of releasing soot when upset, live in a massive manor located deep in the mountains, isolated from other humans. When a Shadow child approaches adulthood, they are given a Living Doll who serves as both their attendant and their second half—representing the faces they might have possessed were it not for their complexion. Emilico is a cheerful, newly created Doll who attends to a rather soft-spoken master named Kate. Despite their contrasting personalities, Emilico does her best to fulfill her master's needs. As she gains a deeper understanding of her role and duties, Emilico begins to encounter her fellow Dolls and their respective masters, learning more about the purpose of her existence. "Do not fret over trivial matters," is one of the rules all Dolls must follow. But how can the ever-curious Emilico adhere to this in the face of the deep secrets held by the Shadows House?