A doctor named Ed in Scrap City found the mechanical remains of a girl on a garbage mountain one day. It turned out that her brain was still in a state of suspended animation. Ed successfully revived her and renamed her Kelly, but she had lost her previous memories. In addition to being a doctor, Ed was also a bounty hunter. In the battle to catch criminals, he clearly knew the darkness of Scrap City, so he hoped that Kelly could live a happy life like an ordinary girl. But by chance, he discovered that Kelly knew the lost ancient Martian martial arts "Mecha Art". Although she had lost her memory, her body was full of fighting blood, which made her register as a bounty hunter regardless of Ed's objection. Kelly's nature is actually very kind, but her arrogance and competitiveness brought her a lot of trouble. Coupled with her excellent mecha skills and strong fighting power, she was destined to fight non-stop.