The Haibane, enigmatic youths with halos and flightless, grey-feathered wings, live in a sleepy town surrounded by impenetrable walls – only the crows may come and go. Reki, an older Haibane, discovers a new cocoon, from which Rakka emerges possessing no memories except that of her dream of falling. Questions of her existence cloud Rakka’s mind as she struggles to learn the ways of the Haibane and to help Reki escape the Circle of Sin.