Everything is a mystery, but there is a answer. It was scary, yet it's wonderful. That is how Reid Calascione felt when he first met Logan Walker. It happens when they captured Logan from a mass crime scene. She look fragile and could almost catch a lot of attention from everyone, yet there's still a story behind that look. Logan was covered with blood and surrounded by a lot of dead bodies. She was the only one alive inside the room. But there is no proof that she was the one who killed them, yet she admitted she was the one who did the crime. They took her for an investigation, but that's the time when Reid realize that Logan was no ordinary. She was a paradox, an enigma criminal.

She is fearless, emotionless and mysterious. That's how they describe her. An assassin, a devil and hell. It started when Colt, the big boss of the Yuzimaki clan found Kurogane at their enemy's basement. She was covered with blood, bruises and a bad smell. She was a thin teenager who got kidnapped by a greedy rich man. But in a coincidence, Colt saw a potential hidden in Kurogane's eyes. He hesitated, but choose to take her. And after that, the new weapon was born. Untouchable and a mysterious one. Not until she got her new mission, a mission that change her life, a mission that will open her eyes and most of all.. her heart.