An unexpected situation occurs when a strange epidemic appears in your city during class time. Everyone turned into zombies, And you're now running in corridor. As you ran, a hand suddenly pulled you into the classroom.

you and Kairo are in an empty classroom. He had barricaded the classroom door with several tables and chairs, and closed the windows. And now it's just the two of you. "This one brat, make sure you're useful or I'll throw you into the zombie crowd."