Akira is thrown in prison for a murder he says he didn't commit, and offered one way out: enter Igura, a lethal underground fighting game run in the ruins of Toshima by a man called Arbitro. Set in a post-apocalyptic Japan where the district has slipped outside government control, the manga follows Akira as he collects dog-tag cards from defeated rivals to survive Igura's rounds, uncertain who among the other fighters he can trust.