Upon his arrival at Shouran Academy Juvenile Detention Center, Yoshiaki Maeda finds himself sharing Cell 4 with fellow inmates Gou Iwakura, Masafumi Yoshioka, and Mitsuru Yamanoi, all of whom have different charges and sentences. Trapped within the walls of the detention center, Yoshiaki, who already harbors a negative outlook on life, soon learns of a fierce power struggle brewing amongst the inmates. However, matters take a turn for the worse when an unexpected zombie apocalypse hits the outside world, with one van carrying infected individuals crashing into the detention center, thereby unleashing a deadly threat on everyone inside.
