In the year A.D. 2115, the once-renowned nation of Japan has been renamed as the "17th Far East Imperial City Management District," with the pledge of settling turmoil in exchange for the populace relinquishing their customary luxuries. Expecting life to remain unchanged, they were caught off guard by the impending catastrophe that was about to befall their society. A rare pathological condition called "Degradation" was steadily spreading across the globe, dissolving human bodies into grains of sand. Caught in a multi-dimensional clash between his own reality and the alternate world of "Frontier S (Stratos)," Tohru Kazasumi, an ordinary student, must battle against his doppelganger and prevent their destinies from intersecting. Can these two worlds ever hope to attain peace?