Touru Souma was a hacker in Steppen Wolf, a rogue group of four who caused mischief in the wired world. But during their final hacking session, they attacked the government agency known as FLAK and Touru’s friend Yuuya died in the process. Haunted by his memories, Touru vows to find the ones responsible for murdering Yuuya, even if it means he must join the enemy to do so. Further complicating the matter is the emergence of the terrorist organization Fei Dao; but the largest challenge Touru must now face is his forgotten memories – especially one involving a girl who continuously reappears in reality...