"Learn to stand on your own." This is the story of the 'caterpillars' crawling on the ground as they grow wings and become butterflies. Riku Atomi, who was once bullied, has always protected himself by "acting with just enough confidence" so that he would never be looked down upon again. One day, after trying to stop the bullying in his class, he draws the attention of "Hokuto-Ren," the most feared delinquent group in town, and ends up being framed for a crime. The ones who come to save the desperate Riku are the members of a mysterious group called "The Crawlers." Meeting these comrades and overcoming his own weakness, the boy prepares to confront true evil.