Ao Gennai is an ordinary first-year high school student until a mystery item is brought to her door one day. Gourai, a miniature humanoid robot capable of mobility and battle known as a Frame Arms Girl, is discovered within. Gourai is the first of her type, with a very powerful AI that allows her to create a personality, learn, and evolve in the same way that the human mind does. Following Gourai's activation, Ao is thrown headfirst into the world of Frame Arms Girls, as more and more of the sentient robots arrive at her front door. Ao is determined to gather as much information is can on the Frame Arms Girls and their fight, thanks to a sizable monetary incentive.