Manga Fort of Apocalypse

Accused of the murder of Yoshiaki Maed, he had just arrived at the Shuran Academy Youth Detention Centre. He is placed in cell 4 and soon is greeted by his cellmates Gu Iwakura, Masafumi Yoshioka and Mitsuru Yamani, who are detained on various charges and sentences. Already believing that life is full of misery, Yoshiaki, to her own nightmare, discovers that the prison is in the midst of a ruthless struggle for power. But the situation becomes even more dire - prisoners and employees know that the outside world has been plunged into chaos by an unexpected zombie apocalypse, and a van with infected people has only crashed into the slammer, bringing them into contact with the undead at one point.