In the distant future, a polluted world has been overtaken by havoc-wreaking creatures called Limbeekoon. Humanity, having been forced to relocate itself, must live in isolated mobile cities called Regios. A mysteriously skilled fighter named Leyfon Alseif enrolls in the Academy city of Zenri and is immediately noticed by Nina Antalk, leader or the 17 Military Arts Unit. He then reluctantly joins her squad, uncertain of what future awaits him and his new teammates within the city as well as the impending dangers in the midst of a plagued world.