Ao Gennai, an ordinary high school freshman, has her life turned upside down when a mysterious parcel arrives at her doorstep. Inside lies Gourai, a petite robot named a Frame Arms Girl with remarkable AI capabilities. As Gourai evolves a personality akin to a human's, Ao dives into a world brimming with these sentient machines landing at her residence. Motivated by a lucrative reward, Ao embarks on a quest to unravel the secrets of the Frame Arms Girls and their combat prowess, intertwining their journey of self-discovery with her own.