A.D. 2115—the island nation once called Japan is now known as the "17th Far East Imperial City Management District." Citizens were promised a life of peace in exchange for some of the comforts they had grown accustomed to. People believed their lives would never change and that tomorrow would be just like today. No one suspected the impending doom their society was about to face. "Degradation"—a rare disease causing the total disintegration of the human body into a mere pile of sand—was slowly but surely spreading throughout the world. Tohru Kazasumi, an ordinary student, becomes embroiled in a multi-universal battle between his world and the parallel world of "Frontier S (Stratos)." This means Tohru must fight his alternate-world self. Their futures collide as their paths cross. Will both worlds ever find peace?