The main character’s name is Parris. He is a 17-year-old high school student who wants to end his life at an abandoned building behind the school. But there was a student at the same class named Ashira who came here first and had a plan like him.
Parris saw Ashira committed suicide in front of his eyes. But the next morning at school, Ashira is still alive and studying in the classroom likes nothing had happened.
And that is the beginning of their relationship to solve the mystery of a suicidal girl student at an abandoned building behind school two years ago.

[From the official website]