Fort of Apocalypse Vol. 1 (Kodansha, 2015)

Yoshiaki Maeda has been falsely accused and detained, along with delinquents from all over the Kanto region, in the juvenile correctional facility, Shouran Institute. Yoshiaki is as typical as a boy can get, so when he finds himself living in this violence-ridden prison, he can't think of anything worse. His cellmates, Iwakura, Yamanoi, and Yoshioka, are a cunning crew and soon Yoshiaki finds himself pulled into a feud going on in the prison. Then suddenly, a prison van crashes into the facility and what shambles out of the wreckage are flesh-eating zombies… and so the curtain is raised on this bone-chilling story of panic and horror!