Zombies conquered the land of Tokyo.
Without hope, in underground shelters, people lived quietly.
Hisako, a girl who grew up underground, heard the word “school” from her grandmother.
School is where children play and learn. It is a paradise for young people. The best place to spend their youth.
Hisako dreamed of this “school”, and one day, she was on an underground train heading above ground. What awaits her? Despair…