In a world where demons physically manifest themselves through people, Astra and a band of exorcists have captured Estella, a woman heavily possessed by demons. Estella is being transported to a place to be freed from the demon's possession and to remember who she was, but an ambush forces Astra and Estella to endure each other as they try to get Estella the help she needs. Along the way, they'll learn who Estella was and about each other and what is keeping them from being good and saintly.