Ikuo Ryuuzaki and Danno Tatsuya are 2 orphaned boys who were looked after by a woman they called 'sensei'. Following their sensei's brutal murder, the two vow to hunt down her killers and the police officers who neglected to properly investigate the case.<br /><br />15 years later, Ryuuzaki is a police detective and Tatsuya has become the leader of a group of mobsters. Helping each other out behind the scenes, they strive to rise to the tops of their respective fields so that they may exact their vengeance.