The heroine, Rinne Natsume, thought she lived her life thinking she was just an ordinary highschooler. Until she found out her true purpose of her existence. A few months before her family was attacked by demon cult worshipper, and her father was killed. At that time, she awakened to the power of the “Grim Reaper” that she had hidden within herself and defeated the cult members. However, her peace was short-lived and she was soon captured. The head of the cult branch, Akuta, directed his anger towards Rinne for the injuries her father had caused him. Just then, the wandering exorcist Shindou Setsuna and Yuka appeared, They fought bravely but were surrounded by numerous cult followers. What kind of fate awaits them?