Kohaku is an angel from haven. She was was sent to the human world with the mission to find Hisui, who's an angel also. But, she was accidentally trapped in a tree and being teased/harassed by a crow. Then, Shuuichiro came by and saved her from the crow. After being rescued by Shuuichiro, Kohaku asked to grant this man a wish for returning his favor. But Shuuichiro wasn't seem to be very happy about this. He reluctantly let Kohaku live with him until there is a wish that he wants she to grant for him.