Yuri, who likes to read, is kind, smart and the ranked 1 in class. She is one of the ones her classmates look up to because she is also the class president. She only has one friend because she focuses too much on his studies and grades, that is Mirito, her childhood friend and crush. One week later, a mysterious student transferred to the school and immediately became popular because of his charm and gentle face. But what Yuri wonders about is the series of mysterious deaths of students since this student arrived. Everything changed when Mirito became one of the victims. Yuri did not hesitate to investigate and use her own intelligence to catch the perpetrator and avenge Mirito. But she didn't know that the possible consequences of the truth would completely change her life.