Disc Demon - a mysterious professional killer, no one knows her true appearance and name. Legend has it that the prey she targets will hold a bloody butterfly in its hand, which seems to be a gift to the prey to go to heaven. She was adopted by her boss since she was a child and trained to become a professional killer. She lives a life that is not what a 17-year-old should have. She is cold to people, expressionless, and her emotions are nonsense. During the day, he is a silent student, and at night, he is an angel killer with a weird smile. In order to complete the task, she was sent to an aristocratic academy and met a love she had not seen in 17 years. She learned joy, anger, sorrow, and caring for others. God loves to play tricks on people. The love and hatred of the previous generation continue to be played out in this generation. . . . . .