In the mysterious mansion known as "Shadow House," where no visitors ever call, live the "Shadows"—a faceless clan who mimic the ways of nobility—and their loyal servants who serve as their "faces." These servants are known as "Living Dolls."

Guest, a Living Doll, strives every day to be of use to their faceless master, Akito Shinonome.

While Shadow children are forbidden from leaving their rooms, Guest grows by interacting with other Living Dolls during the occasional grand cleanings of the children's wing and by learning many things from Akito. Furthermore, Guest's positive and cheerful personality begins to gradually change those around them, including Akito himself.

Eventually, the day of the "Debut" arrives—the day when Shadow children must demonstrate their qualities. After overcoming various trials, Akito and Guest successfully pass the debut and are treated as adult Shadows. However, as they begin to move through the mansion, the bizarre nature of this place slowly comes to light.

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Shadows consider themselves and their Living Dolls to be the same entity, so they usually give their Living Dolls names similar to their own.