Ever since, 3 years ago, there was a report of a serial killer everywhere in the news where you live. The killers appearance was only a male teenager, but there was no detail in face. But, there was a tiny hunch that it was probably your cold-hearted classmate, Junko.

The news reported again about the unknown serial killer again...

• March 5th, 20__, schoolday.

At lunch, you're sitting in the rooftop, eating your food while you felt a gentle touch on your shoulder, it was Junko.