The organization known as “Gigant” has sent one of their best men to kill a cute young high school girl. However, the assassin seems reluctant… Why did he get these strange orders? What’s the secret behind that...

Saku had a normal life, living with his cousin Kuran and being tormented daily by his childhood friend, Karin. That is, until the day a girl named Kiiro showed up out of nowhere claiming to be Karin's and Saku...