Aika Sumeragi, a 16-year-old high school student and newly licensed C-class salvager, scours earthquake-submerged ruins for lost treasures. Orphaned during a catastrophic quake that claimed her scientist parents, she was raised by salvager Gozo Aida, who honed her combat, firearms, and salvaging skills. Unbeknownst to her, genetic experiments conducted by her parents amplified her physical traits, enabling her survival—and awakening a latent alien entity within her. This symbiotic presence shields her from external manipulation and equips her to battle extraterrestrial threats, such as energy-draining tendrils lurking in the ruins.

Despite her prowess, Aika’s chaotic salvaging schedule leaves her perpetually tardy to class. By 19, now a university student, she probes disappearances at a Catholic school tied to alien forces, reluctantly leveraging her otherworldly powers to confront the menace. Her pragmatic methods often clash with allies like Gust, who disputes her abrasive tactics.

Aika’s abilities hinge on a golden ultranate bustier, which activates a transformation into Shivie Aika—a superpowered state marked by dark skin, azure hair, and overwhelming strength. She avoids this form, uneasy with its flawless appearance. Her interactions with peers like Eri Shinkai and Karen Minamino expose her flustered reactions to overt sexuality, contrasting their casual demeanors. Karen, a clone entangled in biogenetic conspiracies, becomes pivotal in missions unearthing ancient technologies and truths about Aika’s origins.

Torn between her salvager duties and the moral weight of her enhancements, Aika navigates her alien-linked identity while shielding others from the dangers her dual existence attracts.