Just another Orphanage...or is it?

Iruka Shitaku, a young girl in New Japan, is another orphan in this post-apocalyptic world. She is brought to Yūgure Orphanage, which issurrounded by tall wire link fences, keeping the outsiders out. The stern, mysterious Mrs Kakinoki is the headmistressof the orphanage. She brings her to her room, which she shares with a girl named Kaen Shinzō, who tells her about the orphanage. It was designed as a prison, not to keep others out, but keep them in, from escaping.