Tachibana is a member of the manga club, and he joined because he likes the club president, Nagisa Shirakaba. One day, curiosity gets the better of him and he takes a look at Shirakaba's manga draft only to find out that she's been drawing an adult trap manga.
When Yuko randomly runs into her aloof classmate Arisa one day, she's delighted to get a chance to get to know her! She cheerfully accompanies her to Shibuya, where Arisa says she has an important job that only she can do. As the situation turns violent, Yuko realizes that the mysterious Arisa has a lot more secrets than she could have guessed. Is Arisa involved with the urban legend of the "Execution Girl," who punishes evildoers?