In 2022, the world is afflicted with a mysterious phenomenon. Adjoining multi-dimension world assimilates and becomes another space, dimension assimilation phenomenon called "Petulation". Humans can't approach these areas and their number keeps increasing... One day, Kuroudo receives summons from the government to help the related scientific investigation at Shin Shinonome Academy located on the newly reclaimed land in Tokyo bay. He has no idea what is going on. But the world gets closer to the destruction little by little. All he has is his skill of swordplay and one sword. There he meets others, whom just like him are destined to fight for the future of mankind...