A doctor named Ed in the scrap iron city found a girl's mechanical remnant on a mountain of garbage one day. It turned out that her head was still in a state of suspended animation. Ed successfully rescued her and renamed her Kelly, but she had lost her previous memory. In addition to being a doctor, Ed is also a bonus hunter. In the battle to arrest criminals, he knows the darkness of Scrap Iron City, so he hopes that Kelly can live a happy life like an ordinary girl. But by chance, it was discovered that Kelly knew the lost ancient Martian martial art "Mecha".
Although her memory is lost, her body is bleeding from battle, causing her to register as a bonus hunter despite Ed's objections. Kelly's nature is actually very kind, but her pride and competitiveness cause her a lot of trouble. Coupled with her excellent mecha skills, her powerful combat power is doomed to keep fighting
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