Nazoo Tokumi, a genius girl with excellent deduction skills solved murder cases for her famous detective father. She was the one who solved his murder cases four times a week when she was in elementary school. She followed the will of her father who was killed by seven villainous criminals, and she blames herself for his death. However, at her high school where she entered, she couldn't stand the murder that happened in front of her and decides to get back into the mystery solving business.