Humans dwell on the star Vega 12,000 years after the events of Genesis Aquarion, under continual assault from trans-dimensional monsters known as Abductors. These foes are from Altair, Vega's sibling star, and they invade Vega in search of human life. To counteract the Abductors, a group known as Neo-DEAVA was founded as a countermeasure. They operate Aquaria, sophisticated mecha suits, and are rigorously divided by gender. Boys and girls are not permitted to interact with one other, and they are even forbidden to fight on the same battlefield. When a sophisticated Abductor mecha suit joins the fray, things take a surprising turn. Mikono and Amata, two teens, are drawn into the dispute. When Amata summons an Aquaria and initiates the Forbidden Union between man and female, he unwittingly breaks a taboo.