Early 21st century. Mysterious creatures have caused the Earth to fall into ruin. Despite the murderous air, the 15-year-old boy, Kei Ano, joins the government-approved organization, Spirits, to get out of the boring days. Among them, Kay meets the mysterious beautiful girl Amara, and she is attracted to her. Eventually, Kay, who has completed post-training training, will be assigned a task. It was to board a giant humanoid battle machine called “Devadasy” and fight enemy life forms. Amara is the other pilot of Devadathy, who is operating in pairs. Who is she? And what is the mysterious robot “Devadasy”?