Yeonrin or Kim Yeonrin, an ordinary student in Seoul International High School. She has good reputation in that school. Until one day, a new student named Orion came to Yeonrin'school. Orion came from Italy with mysterious background. Her attitude shows something wrong with her. Since her arrival, appeared several murder cases. All students at the school accused that Orion is the culprit. But Yeonrin believe that Orion is not the culprit. So Yeonrin and her friends decide to investigate the murder case