Despite being a first-class Ninja of the so-called "Tekki" (Iron Demons), she failed to complete one mission of hers because she didn't want to kill a young boy. After fleeing from her superiors, she finds herself waking up in the mansion of a young landlord, where she tries to begin a new life without killing ever again. But when the mansion is getting attacked and all the guards being killed quickly, she has to fight again.
