Although Kurenai Shinkuro seems like a normal high school boy at first sight, he is actually a troubleshooter who settles various sorts of problems secretly. One day, Juzawa Benika, whom he respects as a top-notch troubleshooter, asks him to guard a little girl, Kuhohin Murasaki. Although he is reluctant to accept Benika's request, Shinkuro finally accepts because he wants to be recognized by her professionally, and because he is moved by Murasaki’s sad look. The next day, Shinkuro goes to school despite misgivings about leaving Murasaki alone in her room. However, he finds that Murasaki is missing upon his return.