The story revolves around two angels who bring death. These are young girls who are complete opposites. However, there is an invisible thread that connects them: they both bring death. Kirika doesn't remember anything about her past life, but she is certain that it holds many frightening secrets. All she knows how to do is kill. Mireille is a successful professional assassin. A strange bond is formed between the girls, making them both close friends and bitter enemies...