It was just another peaceful day at Rosi High School. Students were in their classrooms, on the playground, in the auditorium... in the middle of their lessons.

However, looking outside, the clear blue sky that hadn't a single cloud had suddenly turned dark like a midnight sky. It was as if someone had intentionally turned off the lights.

The teacher went out to search the hallway to see what was going on, but was killed in an instant by a strange creature prowling the corridor. The students who saw this knew immediately. This place was no longer the Rosi High School they once knew.

With escape as the goal, let's try anything. There might be survivors in other classes.