The Last Hope.Since 2021 humanity has been struggling against a parasitic biological agent known as the Gastrea Virus as it ravages the planet. In 2031 Rentaro Satomi of the Tendo Civil Security Agency investigates a Gastrea infection in the Tokyo Area and discovers a masked man who states his goal to destroy the world. Enju Aihara encounters the fleeing infected victim as he morphs into a giant Gastrea spider. Rentaro and Inspector Tadashima of the Tokyo Police quickly arrive on the scene, Enju makes quick work of the creature after Rentaro weakens it with his black Varanium bullets. Rentaro delivers his mission report to his superior and friend Kisara Tendo and receives a severe scolding for forgetting to collect the company's payment for assisting the Tokyo Police. With the source of the recent Gastrea infection still elusive, Rentaro visits his teacher, Sumire Muroto and learns that it may be using a camouflaging ability to avoid detection. The next day after dropping Enju off at school, Rentaro reflects on humanity's war against the virus and their last hope for survival: the Cursed Children.