Rakka awakens from a dream of falling through the sky and emerges from a large cocoon into the Old Home, where she is welcomed by a group of girls who have small wings on their backs and shining halos above their heads. As she grows, Rakka’s own wings sprout and a halo is placed on her head; she is then instructed to begin work in the nearby town of Grie. She soon discovers that both the town and the world she inhabits are confined behind a tall, impenetrable wall, which only the mysterious Toga is allowed to leave.