The bright and cheerful Emma is an 11-year-old orphan living in Grace Field House, a self-contained orphanage housing her and 37 other orphans. They lead an idyllic life, with plentiful food, plush beds, clean clothes, games and the love of their “Mom”, Isabella. Their education is seen as an important part of their development, and Emma with her two best friends Norman and Ray, always excel in the regular exams. The orphans are allowed complete freedom, except to venture beyond the perimeter wall or gate which separate the house from the outside world.
One night, a girl named Conny is sent away to be “adopted”, but Emma and Norman follow with her favorite stuffed animal toy. At the gate, they find Conny dead and discover the truth about their existence in this idyllic orphanage – to be raised as meat for demons. Emma and Norman plan with Ray to escape from Grace Field House with the children, but Norman is taken off to be “adopted”. Emma and Ray then decide to escape with some of their older siblings, leaving the younger children behind.
The escapees find life outside Grace Field House is filled with dangers, but under the leadership of Emma and Ray, they become determined to return to free their remaining siblings, along with children from the other Farms. They encounter demons of all descriptions, including Mujika and Sonju who aid them in their quest. Emma and Ray later meet up again with Norman and together with their allies, they fight a battle for freedom against the demon queen Legravalima and the human Peter Ratri who manages the Farms. Eventually, through her own determination, Emma secures the freedom of all the children and re-forges “The Promise”, but at the cost of her own memory.