Scarlett Blackwood entered an aristocratic school, Blackwood Academy, as an ordinary student. On the surface, she did it for a scholarship, but in fact, she did it to avenge her sister who died in this school a year ago. She brought her sister's diary to school and found the four most suspicious men in the diary. During the day, she pretended to be naive and sweet among them, and at night, she relied on her diary and the clues she collected during the day to uncover the truth. Her surname was the same as the school's name, and she wanted to explore the truth behind her sister's death and the relationship between this school and her surname.
