The Promised Neverland

Emma, Norman, and Ray are the three most brilliant children the Grace Field House has produced in decades. Unlike in a typical orphanage, they, and their fellow children, eat well and are given an intensive education. However, despite living in a peaceful environment with fun games and a caring mother, there's something not quite right. When six year old Connie is "adopted" by foster parents, she forgets her favorite stuffed rabbit, and Emma and Norman sneak out to return it to her. When they arrive at the scene, the two realize exactly why they had always been isolated from the outside world.