Falsely convicted of murder, sixteen-year-old Yoshiaki Maeda is locked inside the Shouran Institute, a juvenile detention facility packed with delinquents from across the Kanto region. His cellmates are the volatile Masafumi Yoshioka, the silent Gou Iwakura, and the sharp-tongued Mitsuru Yamanoi. When a prison van crashes into the grounds and flesh-eating attackers shamble out of the wreckage, the dead turn on guards and inmates alike. Maeda and his cellmates fight their way out of the block and then past the walls, into ruined cities far worse than the prison they fled.