Toru works in the underworld to cover the medical expenses of his mother. One day his boss gives him a job. That is to get rid of his senior who has made a mistake. The boss's command is absolute. If he doesn't get rid of his senior he will be killed. But it isn't easy for him to get rid of his senior, who had took him under the his wing since Toru was a newcomer. He is faced with no choice. So what does Toru decide to do...
