Emma, Norman, Ray, and many other "siblings" live at an isolated orphanage cut off from the outside world. They live a charmed life surrounded by friends and watched over by Mama, their caretaker, until they leave the house for a foster family by the age of twelve. The only rule is that they must never venture outside of the gate that isolates them from the rest of society, for dangers await. But one day, the children learn the true horror of what's in store for their short lives...
The Promised Neverland
The Promised Neverland: Norman Kara no Tegami (Light Novel)