Yu-ee, who lost her parents at a young age, is now a teacher at Eung-bo High School, where her father also taught 20 years ago. She moves into her childhood home, where she stumbles upon her father’s diary. Wanting to know about the truth behind her parents’ suspicious deaths, she traces her father’s steps. The deeper she gets, the weirder things become. What happened on the day of the diary’s last page?