In the early 1990s, experiments were carried out secretly in Japan. Two different methods were used in the experiments. One method involved forcing stress upon expecting parents and, when the baby was born, provoking the baby into mutations and developing their special abilities. The other method involved birth to babies having abilities of animals and insects. The special abilities were derived from gene manipulation. Subaru, Saya and others were born from those experiments. Subaru possesses incredible strength and vision. Saya possesses super hearing abilities. They both grew up in the same facility. They work for Koichiro Watase, who is the senior Vice-Minister of Foreign Affairs and has lofty ambitions as a politician. Koichiro Watase then orders them to find the runaway daughter of a powerful politician. The runaway girl has in her possession a secret file. Subaru, Saya and others become involved in the slaughter group "Ageha." The group is led by Manabu.